I have the 8BitDo Wireless USB Adapter and a DS4 model CUH-ZCT2U.
I tried to do this on WiiU today, with poor results.
When added as a controller in HIDtoVPAD homebrew v0.9, it randomly inputs up and left on the sticks and D-pad.
My PS4 dualshock is synced with the adapter, but doesn't do anything.
The adapter performs these directional inputs whether a controller is sync'd or not (spooky).
I tried to cook up a config, but couldn't seem to make a difference.
The vid&pid of the 8BitDo USB Adapter are:
[vid=0x045E,pid=0x028E]
If anyone can make a working config file, I'm happy to test it out.