I visually verified the raw rom of fabfred, all is good. It looks like it's working in MAME, gotta finish up before pushing it to the git repository.
I'm surprised how many of these Gakken(the original manufacturer) released. Google for "ゲームロボット" - Game Robot 5 - Game Robot 9(this one) - Game Robot 15(LCD) - Game Robot 17(LCD, Doraemon version) - Game Robot 21 - Game Robot 25 - Game Robot 50, looks like a 'modern retro' remake:
