Hello. I have my eye on this game. Is it legit to play on emulator?

I don't think so but I don't see any rule stating so.

normally in speedrunning you can use emulators as long as the game in the emulator is the same as the real one and as long as it isnt in the rules. but you could ask the mods to be sure 10/10

Emulator is not allowed. It changes a lot of the challenge that comes from controlling the game precisely if you were to bind it to mouse and keyboard or a joystick. It becomes a different type of challenge if that makes sense. The main concern is maintaining what makes the game challenging in the same way. On that note, because the game is timed in in game time ISO loader would be fine even though it speeds up loads.