Bob Hackett & Sander Kingsepp
20 May 1939:
20 December 1940:
Cdr Oyama Toyojiro (49) (former CO of I-15) is appointed Chief Equipping Officer.
13 February 1941:
Completed and attached to Yokosuka Naval District. Cdr Oyama is appointed CO.
31 July 1941:
Cdr Fujii Akiyoshi (49) (former CO of I-3) is appointed CO.
I-9 is assigned to Vice Admiral Shimizu Mitsumi's Advance Expeditionary Force (Sixth Fleet) as flagship of Rear Admiral Sato Tsutomu's SubRon 1's I-15 through I-26.
21 November 1941:
Departs Yokosuka with ComSubRon 1 RAdm Sato Tsutomu aboard in company of I-15, I-17 and I-25, carrying a Watanabe E9W1 "Slim" floatplane.
2 December 1941:
The coded signal "Niitakayama nobore (Climb Mt. Niitaka) 1208" is received from the Combined Fleet. It signifies that hostilities will commence on 8 December (Japan time). Mt. Niitaka, located in Formosa (now Taiwan), is then the highest point in the Japanese Empire.
7 December 1941: Operation "Z" - The Attack on Pearl Harbor:
Off Hawaii. I-9, with Rear Admiral Sato embarked, patrols north of Oahu during the attack on Pearl Harbor. Its mission is to reconnoiter and attack any ships that try to sortie from Pearl Harbor.
9 December 1941:
I-6 reports sighting a LEXINGTON-class aircraft carrier and two cruisers off Oahu heading ENE. Vice Admiral Shimizu in KATORI at Kwajalein orders all of SubRon 1's boats, except the Special Attack Force, to pursue and sink the carrier. I-9 surfaces and sets off at flank speed after the carrier.
11 December 1941:
700 miles NE of Oahu. At 1340, I-9 battle-surfaces on unarmed Matson Lines' steamer LAHAINA (ex-WEST CARMONA, ex-GOLDEN STATE) returning to Hawaii after the outbreak of war with 745 tons of molasses and 300 tons of scrap iron. After surfacing off LAHAINA's starboard quarter, the submarine first fires a warning shot. The crew abandons ship after transmitting an S.O.S. signal. Cdr Fujii fires no less than 25 shells for 12 hits (8 starboard, 4 port), setting the superstructure afire.
12 December 1941:
In the following morning, the crew attempts to reboard the ship, but the fires and flooding are out of control. LAHAINA explodes, capsizes to port and sinks around 1230 at 27-42N, 147-38W. Two LAHAINA sailors die of exposure, two commit suicide. Thirty survivors reach Kahului, Maui, on 21 December. 
13 December 1941:
The Imperial General Headquarters orders the IJN submarines to shell the US West Coast. VAdm Shimizu issues a detailed order on the targets. I-15, I-9, I-10, I-17, I-19, I-21, I-23, I-25 and I-26 are each to fire 30 shells on the night of 25 December. Rear Admiral Sato, aboard I-9, is charged to execute the order.
19 December 1941:
Arrives off Cape Blanco, Oregon.
22 December 1941:
Departs her patrol sector for Guadalupe Island area.
27 December 1941:
Most of the I-boats off the coast have depleted their fuel reserves. Vice Admiral Shimizu cancels the shelling.
1 January 1942:
Arrives at Kwajalein.
January 1942: Operation "K-1" - Flying Boat Attack on Pearl Harbor:
The Naval General Staff develops a plan to raid Pearl Harbor using two large Type 2 four-engined Kawanishi H8K1 Emily flying boat bombers. The objective of the attack is to disrupt ship repair activities. The plan calls for the planes to depart Wotje in the Marshalls and fly to French Frigate Shoals in the Hawaiian Islands (500 miles WNW of Pearl Harbor) where they are to be refueled by I-class submarines.
1 February 1942:
Kwajalein is attacked by planes from USS ENTERPRISE (CV-6). Two hours later, Headquarters Sixth Fleet orders I-9 and the other boats of SubRon 1 to put to sea and intercept the enemy carriers. After their return, I-9 departs that same day, carrying a E9W1 floatplane on her second war patrol.
5 February 1942:
At Kwajalein. Five submarines are selected to participate in Operation K-1. I-9 is assigned to take up station midway between Wotje and the Shoals and act as a radio beacon for the two H8K1 Emily flying boats. I-19, I-15 and I-26 are to refuel the flying boats at the Shoals. I-23 is to standby south of Hawaii, provide weather reports and act in an air-sea rescue capacity. The submarines depart for their stations.
7 February 1942:
Arrives to the area 200 miles S of Hawaii.
23 February 1942:
The E9W1 floatplane from I-9 conducts a nightly recce flight over Pearl Harbor. Due to limited visibility the pilot and observer cannot identify any ships in the harbor. During recovery after return, both wings of the plane are damaged.
28 February 1942:
Departs her patrol sector to participate in Operation K-1.
1 March 1942: The Second Air Attack on Pearl Harbor:
I-9 is on station and participates in Operation K-1.
4 March 1942:
After dark, the Emilys arrive at French Frigate Shoals, refuel and take off again for Pearl Harbor.
5 March 1942:
Seven hours after departing French Frigate Shoals, the flying boats drop eight 550-lb. bombs on Honolulu through an overcast. They achieve no significant results and return to the Marshall Islands.
13 March 1942:
I-9 acts as radio-beacon-cum-communications relay platform at Point M (19-00N, 174-20W).
16 March 1942:
Vice Admiral, the Marquis, Komatsu Teruhisa (former CO of CA NACHI) assumes command of the Sixth Fleet (Submarines).
21 March 1942:
Returns to Yokosuka.
15 May 1942:
Departs Yokosuka for Aleutians on her third war patrol, carrying an E14Y1 Type 0 Glen floatplane.
17 May 1942:
Arrrives at Ominato.
19 May 1942:
Departs Ominato to support the invasion of the Western Aleutians.
20 May 1942:
Reassigned to Northern District Force.
21 May 1942:
Rear Admiral (later Vice Admiral) Yamazaki Shigeaki's (former CO of old CA YAKUMO) SubRon 1's I-19, I-9, I-15, I-17, I-25 and I-26 is tasked to carry out preliminary invasion reconnaissance of the Aleutian Islands. I-9 departs Yokosuka for Kiska.
24 May 1942:
At dawn, I-9's E14Y1 floatplane reconnoiters Kiska and Amchitka, Aleutians. The pilot reports that Reynard Cove on Kiska is best suited for a future landing. No troops or barracks are sighted ashore. He also reports that contrary to the earlier reports there is no airfield on Amchitka.
26 May 1942:
Around 0500 (local), I-9's floatplane reconnoiters Adak and Kanaga. The pilot counts eight bivouacs and other similar buildings on Adak.
29 May 1942:
Provides distant cover for Rear Admiral Kakuta Kakuji's CarDiv 4.
5 June 1942: Operation "AL"- The Invasion of the Western Aleutians:
Twenty ships of the Vice Admiral Hosogaya Boshiro's (former CO of MUTSU) Fifth Fleet, including light cruisers KISO and TAMA, three destroyers, three corvettes, three minesweepers and four transports land Rear Admiral (later Vice Admiral) Omori Sentaro's (former CO of ISE) Occupation Force on Attu, Aleutians without opposition.
6 June 1942:
Joins a patrol line off Aleutians.
7 June 1942:
Captain (later Rear Admiral) Ono Takeji's Occupation Force occupies Kiska, also without opposition.
8 June 1942:
The patrol line is shifted to Kodiak area.
15 June 1942:
I-9's floatplane reconnoiters Kodiak Naval Air Station. On that same day, I-9 attacks two merchants in the same area, but misses both times.
19 June 1942:
I-9 shells and damages 4,636-ton American troop transport GENERAL W. C. GORGAS (former Hamburg-America Lines PRINZ SIGISMUND) at 56-17N, 146-46W.
30 June 1942:
Reassigned to Advance Force. Departs her patrol sector for Yokosuka.
7 July 1942:
I-9 arrives at Yokosuka.
7 August 1942: American Operation "Watchtower" - The Invasion of Guadalcanal, British Solomon Islands:
Rear Admiral (later Admiral) Richmond K. Turner's Amphibious Task Force 62, covered by Vice Admiral (later Admiral) Frank J. Fletcher's Task Force 61 and Rear Admiral (later Admiral) John S. McCain's Task Force 63's land-based aircraft, lands Maj Gen (later Gen/Commandant) Alexander A. Vandegrift's 1st Marine Division on Guadalcanal, opening a seven-month campaign to take the island.
15 August 1942:
Departs Yokosuka in company of I-15, I-17, I-19 and I-26 with ComSubRon 1 Rear Admiral Yamazaki Shigeaki aboard on her fourth war patrol.
23 August 1942:
I-9 joins the patrol line A off San Cristobal..
24 August 1942: The Battle of the Eastern Solomons:
Vice Admiral (later Admiral) Frank J. Fletcher's Task Force 61's USS SARATOGA (CV-3) and ENTERPRISE (CV-6) launches aircraft that find and sink the light carrier RYUJO. In turn, CarDiv 1's SHOKAKU and ZUIKAKU launch aircraft that find and damage ENTERPRISE. That evening, aircraft from SARATOGA damage seaplane carrier CHITOSE.
25 August 1942:
At 1143, LtCdr Frederick Bell's USS GRAYSON (DD-435), temporarily screening Fletcher's TF 11, spots a "carrier's superstructure" 12 miles WSW. The destroyer is detached to investigate the contact, two minutes later identified as a diving submarine.
At 1223, GRAYSON commences a depth-charge attack, but I-9 foils her approach, turning inside the destroyer's turning circle. After the contact is reestablished, GRAYSON makes another attack, but again I-9 escapes with a hard turn at full speed at the depth of 200 feet.
LtCdr Bell, joined by a Douglas SBD "Dauntless" dive-bomber from USS WASP, conducts a dummy attack to wear the submarine down. After 1329, GRAYSON drops the third pattern of depth charges. I-9 heads due west at 4 knots and the contact is lost until 1347. Meanwhile PATTERSON (DD-392) joins the hunt.
At 1351, GRAYSON commences the fourth attack, but I-9 turns to WSW, making 7 knots. With the fifth attack the destroyer expends her entire supply of depth charges, slowing the submarine down to 4 knots. Buffeted by close explosions, I-9 drops to 440 feet; all lights go out and a small leak appears in one of the forward fuel tanks. Aft bilge pump is disabled.
At 1418, PATTERSON commences her first run, but fails to detect the target in the turbulence created by GRAYSON's depth charges. 1438, USS MONSSEN (DD-436) joins the hunt.
At 1440, PATTERSON establishes sonar contact with the submarine; a few minutes later her lookouts report the submarine is surfacing. The "Dauntless" marks its location with a smoke float. PATTERSON and MONSSEN make one attack each. After a huge air bubble and oil slick appear, the destroyers depart the area, claiming their target as sunk.
I-9 surfaces two hours after the last attack. An inspection reveals some additional damage: two periscopes are rendered inoperable and one radio transmitter temporarily knocked out. Rear Admiral Yamazaki reports the damage to Truk and is ordered to return to base.
30 August 1942:
Arrives at Truk. Undergoes repairs by URAKAMI MARU.
8 September 1942:
Departs Truk for an area SE of Guadalcanal on her fifth war patrol with ComSubRon 1 embarked.
15 September 1942:
Cdr Fujii sights several transports. On that same day, I-9 is reassigned to 2nd Patrol Unit.
23 September 1942:
200 miles SE of Guadalcanal. I-9 briefly chases a transport escorted by one destroyer.
1 October 1942:
Departs her patrol sector for Truk.
6 October 1942:
Arrives at Truk.
13 October 1942:
The staff of ComSubRon 1 is transferred ashore.
16 October 1942:
Departs Truk on her sixth war patrol SE of the Solomons, carrying an E14Y1 floatplane. Reassigned to the "B" Patrol Unit.
31 October 1942:
Reassigned to B Patrol Unit. Ordered to reconnoiter Nouméa, New Caledonia.
4 November 1942:
I-9's floatplane reconnoiters Nouméa airfield and harbor, sighting one aircraft carrier, three cruisers and several smaller vessels.
7 November 1942:
I-9 is detached from B Patrol Unit to conduct aerial reconnaissance of Espiritu Santo instead of I-7.
11 November 1942:
I-9 is ordered to proceed to Shortland.
16 November 1942:
Truk. Vice Admiral Komatsu convenes a meeting of his submarine captains. He announces that the Sixth Fleet has been ordered by Admiral Yamamoto, CINC, Combined Fleet to organize a supply system for the IJA's 17th Army garrison on Guadalcanal.
19 November 1942:
Arrives at Shortland, embarks cargo.
24 November 1942:
Departs Shortland on her first supply run to Kamimbo Bay, NW Guadalcanal, carrying 32 tons of food and ammunition.
26 November 1942:
Arrives at Kamimbo, unloads her cargo, then departs for Truk.
1 December 1942:
Arrives at Truk.
Late December 1942:
Departs Truk for Shortland.
2 January 1943:
Arrives at Shortland.
4 January 1943:
Departs Shortland on her second supply run to Guadalcanal, carrying 21 tons of food in rubber containers.
6 January 1943:
Arrives at Kamimbo, unloads her cargo, then departs for Shortland.
8 January 1943:
Returns to Shortland.
10 January 1943:
Departs Shortland on her third supply run to Guadalcanal.
12 January 1943:
Arrives off Kamimbo, but fails to deliver her cargo, since the anchorage is patrolled by torpedo boats.
14 January 1943:
Returns to Shortland.
16 January 1943:
Departs Shortland on her fourth supply run to Guadalcanal.
18 January 1943:
Arrives off Kamimbo, but cannot release her supply drums underwater.
20 January 1943:
Returns to Shortland.
22 January 1943:
Departs Shortland on her fifth supply run to Guadalcanal, carrying 18 tons of cargo in 120 supply drums.
25 January 1943:
Arrives off Kamimbo, releases 80 supply drums with 12 tons of cargo, but is then driven away by torpedo boats.
27 January 1943:
Returns to Shortland.
28 January 1943:
Departs Shortland on her sixth supply run to Guadalcanal.
30 January 1943:
Arrives off Kamimbo, releases all supply drums, but all are detected and destroyed by arriving torpedo boats.
31 January 1943: Operation "KE" - The Evacuation of Guadalcanal:
A task force of units of the Second and Third Fleets from Truk including carriers ZUIKAKU, ZUIHO and JUNYO, Bat Div 3's KONGO and HARUNA, CruDiv 4's ATAGO and TAKAO, CruDiv 5's HAGURO and MYOKO, DesRon 4's light cruiser NAGARA, DesRon 10's light cruiser AGANO and destroyers, steams north of the Solomons as a feint to cover Rear Admiral (later Vice Admiral) Hashimoto Shintaro's (former CO of HYUGA) destroyer force from Rabaul.
1 February 1943:
Returns to Shortland, departs for Truk on that same day.
4 February 1943:
Arrives at Truk.
5 February 1943:
Departs Truk for Yokosuka.
9 February 1943:
The Japanese successfully complete the evacuation of 11,700 troops from Guadalcanal.
12 February 1943:
Arrives at Yokosuka.
20 February 1943:
Transferred from Yokosuka to Kawasaki's Kobe Yard for repairs. 
1 May 1943:
Cdr Fujii is promoted Captain.
11 May 1943: American Operation "Landcrab"- The Invasion of Attu, Aleutians:
Rear Admiral (later Admiral) Thomas C. Kinkaid's Task Force 16, covered by Rear Admiral Francis W. Rockwell's Task Force 51, lands the Army's 7 th Division that captures Attu.
12 May 1943:
Reassigned to Northern District Force.
13 May 1943:
Returns to Kure.
14 May 1943:
Departs Kure for Yokosuka, arriving on 16th.
21 May 1943: Operation "KE-Go" - The Evacuation of Kiska:
The Imperial General Headquarters decides to evacuate the garrison at Kiska Island, Aleutians.
23 May 1943:
Departs Yokosuka for Paramushiro Island in the Kuriles.
27 May 1943:
Arrives at Paramushiro.
29 May 1943:
Departs Paramushiro on her first supply run to Kiska, carrying 17 tons of ammunition and 2 tons of food.
1 June 1943:
Bering Sea, off Agattu. I-9 is chased by an unidentified destroyer for three hours.
2 June 1943:
Arrives at Kiska, unloads her cargo and departs on that same day, carrying 79 passengers (55 sailors, 10 soldiers and 10 gunzoku construction workers).
8 June 1943:
Returns to Paramushiro.
10 June 1943:
Departs Paramushiro for Kiska on her second supply run to that location to evacuate the personnel of the local midget base. No messages are received from I-9 thereafter.
13 June 1943:
Kiska, 15 miles E of Sirius Point. At 1758 LtCdr (later RAdm) Elliot M. Brown's USS FRAZIER (DD-607) detects a target with her radar 6,900 yards away. FRAZIER closes the range in dense fog at 20 knots and soon establishes sonar contact with a submarine. At 2009 a lookout sights two periscopes at 100 yds.
FRAZIER opens fire on the submarine, scoring a hit on one periscope. The destroyer attacks I-9 with depth charges. Air bubbles, oil and debris rise to the surface, but FRAZIER makes two more attacks to ensure that the submarine is sunk. I-9 is lost with all hands at 52-08N, 177-38E. 
15 June 1943:
Presumed lost lost with all 101 hands off Kiska. Captain Fujii is promoted to Rear Admiral posthumously on this date.
1 August 1943:
Removed from the Navy List.