That's interesting. I read most of his books and I really can't recall anything in that regard. Between he's famous for being a horror author although he wrote a few non-fiction books. The human psyche and inner monologues of the character along with descriptions of villains and why they became the monsters they are, are recurring topics in his books. Might it be that this is the reason why they involve child abuse? Remember Dutroix? He was abused as child.
Anyways I can't really recall any scenes in his books where he delved more into that topic than appropriate.
Edit: I'm trying not to have idols or parasocial relations and it's been years since I read the last SK book. So my memory may be clouded a bit. Other than the scene from "The Jaunt" (which I haven't read), I haven't found anything after a quick search. If it turns out he's a pedo I won't defend him. But regarding from what I know about him as person from the biographical texts, and stuff he wrote on social media and how meticulously he deconstructed evil personalities in his books, I can't imagine this being anymore than a witchhunt.