I do so love INTPs. *sigh*
My INTJ son wonders what he's missed with highschool. I can never show him, although I know it's just crap. So, for this I feel bad. But it just can't be perfect either way. I wish highschool made it easier for you to pick and choose what you utilize them for, but they don't. You buy in whole hog in 9th grade or they make it nearly impossible to access the system. If you go in later, they are likely to place the kid in a lower grade just almost as a punishment, although they say it's necessary for their 'paperwork.'
And my kids start venturing out at 15-16, when they start driving, (and they get out before that) which I think is early enough. By then, they are so independent and darn trustworthy, that there just isn't much to worry about. That is when you can really start seeing the fruits of your labor.