How to keep my son away from the manosphere?

He’s 9 right now and has no unsupervised internet access, so I’m not worried yet. I have told him that men who think women are inferior are stupid and bad. We’ve discussed the fact that there is a lot of stuff on the internet that is wrong and just plain dumb.

I’m not sure what to do when he’s older and has more internet access. Does anyone have any experience or ideas on this?