I was wondering if I could play this game on a PS3 and still submit a legal run that would be added to the leaderboards. It is running on a disc that I own I am not emulating it from the ps store.

Precedent: https://www.speedrun.com/spyro3/run/0y6dpwpm

Ok cool thank you for letting me know about that run.

Every official release is allowed, and I believe emu is as well.

As you can see, wr is on the pstv (official emulation), so even without disc you should be alright.