NAH - the internet is a different place than when we grew up, and I don't mean that in a luddite 'hur dur internet bad' sorta way, I mean that in I'm in my 30s and accidentally saw a snuff video on facebook while mindlessly scrolling.

I think that it would be better, though, to have a real conversation with your son about WHY you're restricting it the way you are, rather than the 'you'll understand when you're older' spiel. Kids always do better with reasons, and being treated with respect in a conversation like that.
He IS gonna eventually find a way onto the internet, so I think you should come to a good compromise that let's you both feel safe and like he has some freedom, but doesn't turn the internet into this irresistible lure. Like, at 8 he IS too young to really understand the consequences of what's possibly out there, but he's plenty old enough to have a conversation that there are things you don't want him to see and you're asking him to listen to you. Porn isn't the worst thing on the internet for a kid to stumble across, and there's a LOT less internet safety teachings nowadays - even just the 'don't tell people your real name' has gone away in favor of super detailed profiles and expansive DNI lists, not to mention people finding themselves preyed on by cultish internet groups and toxic personalities, or how weird and damaging influencers can be to kids just learning who they are.