Well, 16 according to sources (which I think is the average AoC in most of the civilised world) so not really a young child. I think this case is probably more damaging. However the media is very sensationalist about this kind of thing, I think it's a good idea to wait and see before passing too harsh judgement. The statements refer to "nudity" and "naked girls" which for all we know could be pictures from nudist camps rather than actual child porn. If he's actually assaulted any children then yeah, that's terrible and he should have the book thrown at him, but I don't think it's been suggested yet that he has, or even that he's viewed that happening.I think the author of Toriko got prison once for actually paying for a young child for the night, and his manga while put on hiatus did resume after he was out. I doubt this will affect Kenshin much.
People in porn have to be 18+ under that age is illegal in most countries.