not possible to map the cursor and turbo buttons on the super scope

[Ploggy]

It isn't possible to map the Cursor or Turbo Buttons on the Super Scope so they essentially don't work ,the Shoot bind is automatically set to the Touchscreen (WiiU) and works perfectly, there are options in Settings>Input for Gun binds but setting them to Buttons on the WiiU Gamepad have no effect.

[Sanaki]

Controls are documented here, and I can verify they work correctly on PC:
https://docs.libretro.com/library/snes9x/#lightgun

Super Scope goes in port 2, so your -easiest- approach is to bind the lightgun buttons for port 1 in your input settings, then save a remap after changing the mapped port to 2 in port 1 controls.
Cursor = Gun Aux A
Turbo = Gun Aux B

Bear in mind that you do need to be using the Light Gun mode in your core options for that to work. If you're using Touchscreen mode, I don't think those buttons can be bound.