The Skulduggery series has funny combination of fans - mix of 9+ boys and teen girls! It seems to offer different benefits to each audience.
DL is v funny in the flesh and the children really take to him because in spite of the fact he is insulting them at every opportunity. Word of warning, as with all these things - the series gets darker as the story progresses, so you might want to check your DS will be OK with the subject matter.
Ds loves them - he was 9 when he started them. I love them too - witty, well written, good female role models in a 'boys' book! They defn novel e mild peril - but ds is fairly easily scared & hasn't been freaked to date.
Agree re strong females - hence the attraction to teen girls, I think, as well as younger boys looking for an adventure/fantasy story - but I think the two audiences read the books slightly differently iykwim.