M.D.
Why not look in to an iPad? My kids all have one - they got them for Christmas a few years ago - and they love them. They are used for school apps and reading, plus games and some YouTube.
We are open with our kids and they tell us if they run across something that isn't appropriate. They aren't on them 24-7 and we don't have to have controls on it. Maybe try talking to him about what is right and wrong and what to do if he comes across something wrong rather than just blocking it all?