Earlier quoted context omitted.
> If you're stuck at home you might as well study. Exactly. It's a good opportunity for self directed study. I would spend time doing something productive, not traveling.
Self-directed study is challenging, especially for 17 year-olds that don't have anyone (eg parents) who are in tune enough with autodidactism to guide them. One of the biggest advantages of college for me was realizing how much there was to learn and how easy it was to do it (after skating through all of my schooling with straight As), and I only really refined my autodidactic abilities in my mid-20s.
There are probably some core subjects I could usefully have studied. But, in general, I'm probably not going to place out of classes at many schools even if I've deliberately studied for AP tests. So it's not obvious that year of self-study necessarily leads to a shortened or improved degree program.
That's not a reason not to do it of course. But self-study doesn't necessarily lead to greater personal enrichment than volunteering or hiking the Appalachian Trail does.