SNES9x in Dingux runs without the X/B button issue found in the native SNES emulator
I don't know about the Super Punchout Save state, not really sure what you're asking. It definitely support Save States though.
The FX Chip games still won't run in SNES9x yet (so no Starfox or Super Mario RPG)
For my personal plug, Dingux is great, it really opens up new possibilities for the games. If you've got the time, definitely install it.