I would definitely do audit, but my understanding is that AP scores are sent AFTER acceptance in college. So, you might want to check to see if getting good scores (= college credit) would make up for not having high school credit.
That depends on what college/university. Many schools at AP scores, or will look at them if they are sent with the admission info. And others don't look at them at all. Check with the school about this. Just went on a bunch of college tours so I'm fairly fresh with this info.
