Huh. It was Earth Science in 9th, biology in 10th, chem in 11th, and physics in 12th grade for us. We didn't have AP physics. You could take biology as a freshman I think - my younger sister and I ended up in the same bio class. But I don't remember how that affected the rest of her science studies. I think she took chem in 10th, and physiology (an elective) in 11th. But I could be wrong on that.
When I was in 8th grade, there were 3 algebra classes (honors) and all the other classes were pre-algebra. I then took geometry in 9th grade, algebra II in 10th grade, a weird hybrid of trig/pre-calc/calc 1 in 11th grade, and calc 1/calc 2 in 12th grade (AP Calc 2). We didn't have any AP classes until 11th grade, if I remember correctly. I didn't take any until my senior year.
My dad teaches in the same school system and he says all the classes are algebra in 8th grade now, so I guess they're all smarter.