I think that is overly simplistic. My son took the ACT last year in 7th grade as part of Duke TIPS and scored higher than seniors I coach who are going to Georgia Tech.
That suggests he could graduate based on your criteria.
But what this skips is general knowledge that I don’t think is tested as part of the ACTs like history, biology, chemistry, higher math (pre calf and calc), etc.
Maybe kids could be eligible for taking the GED tests (is that a thing?) if they score over a certain level.
We felt differently about our homeschoolers. They started college at the ages of 13, 12, and 13. They are adults now and thriving in their marriages, the community, and careers.