My son, 10 th grader, just told me he wants to take his sky out and Senior classes at the local community college and skip high school so he can pursue his music more in depth. He says school marching band and wind ensemble take too much time out of serious music study. Can anyone else who is applying/has applied to schools like Rice or NW comment on this?
If he takes CC classes, make sure he does them as a high school student, not an early college student so he’s not considered a transfer. I would tend to agree with him about those time-consuming ensembles if he’s preparing for a serious conservatory audition.
At our school, none of the serious (or talented) musicians participated in school band or ensemble. Often they went into the city to conservatory prep.
There is a wide range of experiences for high school aged musicians and one common one is to homeschool or, as you mention taking community college classes, which offer more flexibility (if they are close by). Glassharmonica’s warning about avoiding transfer status as a college applicant, is wise.
One other option: online classes, either alone or in combination with high school classes. Some online classes have a deadline each week for work done, and some are looser.
The Virtual HIgh School is one we used, and we then convinced the school to fund 25 slots for students at the school so that all the courses taken were credited toward graduation. But even if a student just takes a class or classes online individually, the high school can still grant credit: just get it approved beforehand.
Your son sounds mature and it’s wonderful that he is so committed to playing. I would just caution that the “whole person” is important so making sure his emotional and social growth continues along with his musical growth, is important, but you already know that 
That is one reason why we combined online classes with regular high school. The focus was still music outside of school.
My son did (and is still doing) a combination of HS and Running Start classes. His HS orchestra is very rigorous and lots of camaraderie so that and his awesome Latin teacher keep him connected to his HS friends. But, he’s LOVED the community college classes - leaves plenty of time for practicing and as he put it “there’s no busy work.” The workload is manageable and he’s home by early afternoon for lessons/practicing. The other advantage is he’ll be able to “try out” a couple of classes (like Psychology) that’s he is thinking of minoring in at college.
My senior is doing a combo of homeschool and dual enroll classes right now. It’s been a great combo for him. If by NW do you mean Northwestern University in Evanston, IL? I’ve also seen that as NU and I’ve seen NW be other schools too so just checking!
Anyway if he’s interested in northwestern I recommend using an umbrella school or maybe your current school as an umbrella? NU has a odd requirement JUST for homeschoolers that you specifically supply 3 SAT-2 subject tests with your applications. I don’t think it’s weird they want more data and I get that many schooled kids are taking these too depending on where they are applying. But the vast majority of schools are fine with a range of data like AP’s or a DE transcripts or other independently issued grades with a strong ACT or SAT. I think USC is another school that may have this requirement. And maybe you’re doing SAT-2s anyway but it was just not on our radar. My kid was going to try some in June but his April ACT was cancelled (weather) and he had to switch to a June date and then he didn’t have time. Every time he gives up a Saturday morning he misses something music related.
My kid is so busy with ensemble and extracurricular stuff it still hard at times to find enough time to practice. That said, he averages a couple hours a day engaged with performance and music related pursuits and if he were in a B&M classroom he would certainly not be able to do all the extras that he does. He has a nice social life too, but we’re urban and he’s engaged in broader community programs so that helps.
My S stayed in public school but we did greatly scale back the amount of class work for senior year. The decision was made mid-junior year when it became clear that he was going to apply for music schools (BM/audition). Until then, he had a very rigorous schedule including multiple AP and high honor classes. But for senior year, we let him scale back to three music classes and the remaining state requirements and let everything else go. I worried a lot about this but it has turned out to be the right thing, leaving room for extracurriculars like youth symphony, all-states etc. plus lessons and (soon) auditions. He did stay in marching band for the social aspects and he has had to play catch up since that season ended—but I can’t imagine him handling everything on his plate right now and three AP classes as well.
@MusakParent: Northwestern University is NU, not NW. Don’t know why people think it’s NW…this comes up a lot.