Apparently there are nine 00 agents, as seen in Thunderball. There are nine chairs and Bond takes the seventh. Seems to occur again in The World is Not Enough.
002: Bill Fairbanks, killed by The Man with the Golden Gun (though not shown). Bond finds the belly danger who uses the bullet as a charm.
003: Not named, Bond finds his body at the start of A View to a Kill
004: Killed at the start of The Living Daylights by the KGB asassain.
006: Alec Trevelyan in GoldenEye.
008: Bond mentions him when it looks like Goldfinger may kill him, and M says 008 may replace Bond on a mission in The Living Daylights.
009: Killed, dressed as a clown, in a superb sequence at the start of Octopussy.