We didn't "do" high school...our son just went straight to community college in 10th grade. It's tuition free in our county for any high school student who gets high enough scores on their College entrance exam to place them in Comp I and College Alg.
So now, after 3 years in the program, "the kid" is graduating from high school and getting an AA at the same time and will transfer to University as a junior.
Many, many states offer similar programs, and you don't have to be concerned with an "exit exam." We've found the CC profs to be very helpful, not too liberal (some are, some aren't) and the whole CC atmosphere is so much more conducive to learning than your average high school.
After talking to counselors at other universities, I've found some who agree with UVA, some that disagree and some that have never heard of that as a problem! Guess it depends on what the university wants I reckon.
Glad your son was successful--free tuition is awesome!