Sorry if I came across rude. It just hit close to home.
I see the safety issue you have w/your girlfriend and her clothing, but what does a 9 year old girl do to get raped. Nothing. If people are sick they are sick and they are going to attack whoever. If your gf is a B* to strangers, then she probably doesn't have a huge chance of getting attacked. Predators prey on the weak and the meek, not the confident and the strong. They usually go after someone who they don't think will fight back and from the way you described your gf, she would!!
Harassing a girl is inapproriate no matter what in my opinion and I can completely understand where that would upset you b/c it's a total lack of respect for the someone you love and care about.
I think if she's toned down some that maybe she feels like she's compromised with you and you should back down some.
"The thing that is really hard, and really amazing, is givnig up on being perfect and beginning the work of becoming yourself." ~ Anna Quindlen
My body is the temple of the Holy Spirit and I glorify God in it by walking in divine healing and divine health. - I Cor. 6:19