I haven't played it nearly as long as warcrow, but here's what I've picked up.
- There is definitely cussing. It's not rampant but they don't try to avoid it either.
- The combat system allows you to shoot off the arms, legs, and heads of your enemies.
- There are also several scary/gross mutated radiation monsters like "centaurs" that probably would scare the crap out of a 9-year-old.
- Sexual themes are very discreet. The end result is significantly tamer than an episode of a typical prime-time TV show.
The decapitation and dismemberment is probably the biggest concern. Seeing an enemy's head fly off trailing blood is pretty intense for a kid.