I just got it to work with pkhex and ryujinx.
I dragged and dropped the wc9 file into pkhex and hit ok. It didn't add it immediately to my key items. I had to go to a blank spot in my key items list. I scrolled down and had the mystical pecha berry as an option. I clicked it and set it to one. Saved and launched the game and I had it in my key items! I just walked up to the pillow and it was there and I'm starting it now!