just wondering, im not into it since i always guarantee that my copy is legit, but im wondering if speedrunning a pirated version of a game is acceptable for the speedrunning community? like it's allowed to be submitted and approved.

Like kmrd said, unless it's very obvious (some games have anti-piracy measures that change in-game visuals), I think nobody would even question it. Emulator runs don't require you to show that you own the copy of the game either.

Generally, unless it there is a reason that the game would be, in significant any way shape or form, changed, nobody cares.