Kla of PSP Wiki has released a port of Snes 9x that works on the PSP 1.50, you have to renamed the rom to rom.smc and it seems to use the Mem Card exploit.
Cant test it myself as i dont own a PSP 1.50 but you can download Here --> http://psp-news.dcemu.co.uk/snes9xpsp150.shtml
Thanks to Kla and PSP Wiki for the release.
Please post if you get it working etc