How do I convert a snes rom to PSX format and to burn it to a cdr so it'd play on a psx or ps2?

You don't

PSX doesn't have the capabilities to run SNES or even NES for that matter. Buy a used DC. They're cheap and can emulate many older consoles faithfully. :)

Even DC's struggle with SNES, unless dreamsnes has changed alot since the last time I used it... But NesterDC works great for NES games

wont happen