@mattw24 It seems that you have no hotkeys to savestate, and this is why it is not working.
Try it without the trailing 2> /dev/null (this let us see the error messages, if they exist). Just:
grep -R save_state_btn /opt/retropie/configs/all
I suggest you to reconfigure your joystick in emulationstation: press Start and select CONFIGURE INPUT.
Reading suggestions:
https://github.com/RetroPie/RetroPie-Setup/wiki/FAQ#how-do-i-change-which-buttons-to-press-to-exit-an-emulator-with-a-controller
https://github.com/RetroPie/RetroPie-Setup/wiki/RetroArch-Configuration
I'm sure your problem is very simple to solve, and I'm sure that if you read and understand the links above, you'll solve it easily.