From what I understand, many school districts in the USA have rules against this. Or, they have no advertised route for early completion, which is effectively the same thing.
When I was in high school, I only managed to skip one math class. I was forbidden from taking AP physics without first taking non-AP physics, and the school was unwilling to work with me so that I could take classes at a local college (i.e. I wouldn't graduate because they wouldn't help me make the schedule work).
From what I understand, many school districts in the USA have rules against this. Or, they have no advertised route for early completion, which is effectively the same thing.