A low key way we kept track of things was throwing stuff in order into a binder. I always kept a box of plastic sheets and a 3 hole punch handy. Things like brochures for camps and programs, orchestra calendars, master class info, programs for performances, resumes as they came up with them (my kids did some theater, etc). If nothing else, it makes nice scrapbook. But it makes it very handy to flip through and summarize things when it came time to apply and when we started it I certainly wasn’t talking about using it for college. It was all just keep things organized. I also tried to help my kids keep at least their solo repetoire organized into binders as well and we would retire them as they’d fill up.
This is for parents but since it hasn’t been mentioned, the best thing we did toward college when my oldest was about in 8th grade was talk to a financial advisor about what we could afford and how to plan. It can really helps to know how you are going to get to a program. This is a much easier game if you have unlimited funds. But if you’re merit and/or financial aid shopping, it helps to know. Maybe pick a few programs and run through the net price calculators and see how it looks.
Also, I would also work on keeping doors open and making sure academics are looking good otherwise. That can help with admissions and merit money at lots of great options. Give him plenty of chance to try new things and reinvent himself. I have 2 kids who’ve auditioned in music and they were all over the place during high school on path.