Hmm. The OP's daughter is now 16 or 17. Probably doesn't have to worry about "safe" or appropriate SF any more, he's got bigger problems.
I was lucky that my branch library had a decent selection of SF, and put it all in the juvenile section. Heinlein, Norton, Del Rey, DeCamp, Anderson, etc. The long series of Avalon books by various well known authors was dependable.
Conan!
Dorsai!!
I didn't find E.E. Smith, PhD until I was in college, which was a shame. Adventure then, but it would have been fantastic to a younger reader.
First time around, Anderson's 'Virgin Planet' was a good adventure yarn for a kid. Later, the plight of one man stranded on a planet inhabited only by women who reproduced by parthenogenesis but were anxious for the opportunity to stir the gene pool was hillarious. Nothing explicit, mind you, but the thoughts were there, if you were old enough to care.