I've using Raspberry Pi 400 + PyGameZero + emacs for a 8yo. I miss a good book that keeps complexity very low to give him some independence (I need to constantly supervise his steps and what he is understanding at each point).
Have you seen the Raspberry Pi Foundation's book "Code the Classics"? It's a pretty gentle introduction to game programming using PyGame Zero, building old-style games like Frogger. It's quite colorful and meant to appeal to kids, a lot like the old Usborne books.