Seems ever Cussler book I've read has had at least one sex scene in it. Though so far I have only read some of the Dirk Pitt and Isaac Bell series so maybe he is different in others.
As a spy fan growing up I read a lot, though I was reading Fleming by the 6th grade. I would recommend the Christopher Cool/TEEN Agent series by Jack Lancer except it is long out of print and there are no ebooks of course. I'm making my own from my copies. You can find copies online though.
By the time I was really into spies as a kid I was reading the Man from UNCLE books (again out of print but available online), I Spy, and a bunch of others based around 60s Spy shows.
There are some James Bond Jr books out there as well, Amazon suggests them to me now and then since I told it I own all the Bond books. You could try checking out those maybe.
Sorry, most of my "kid spy" material was long, long ago so not to current.
Hope that helps some.