See if you can find a book on python, and work through it a bit. Sit down with him once you know some and try making something basic with turtle or the likes. Your goal is to keep his interest up and not make it a “studying” thing. For a kid the most important part is that he needs to be able to see results of what he’s making. Drawing simple shapes, cool patterns, etc. in python is a nice way to start and it can teach all the basic initial things he needs to know.

There’s also simple robot kits for kids that could be fun to play with, which he could eventually move on to basic electronics to after from.

W.r.t. safe browsing, I’d try blocking egregiously bad stuff with some DNS blocker that you either buy or host using something like pihole, and have a conversation with him about it. Use it to block ads and well known “bad” domain names. (I’m not sure how much this helps here considering he’s 8… but better then nothing.)