Well I know for starters that its only illegal to have the ROM if you do NOT own the original game.
There is some additional options you can change in snes9XTYL to raise up your framerate. If you go to the Misc options in the menu and select the Hack/debug menu.
Inside there turn on Ignore Fixed Colour. Turn off Ignore Windows Clipping. Turn off Add/Sub modes. Turn on Ignore Palette writes. Turn On Fix HiRes Hidden details. Turn On Fast Sprites. Turn off BG3.
Those help alot of the time.