That national orchestra run by Carnegie Hall. Was it NYO? NYO2? If yes, those are much more than “pretty competitive”. Those are INCREDIBLY competitive, NYO>NYO2. If it was one of those, “Congratulations, pay us some money and your child can play at Carnegie Hall!” programs, then much less so. He was selected to perform on From The Top? That’s a big deal, too.
You are dealing with the “Double Degree Dilemma”. If he is at that level, he will find it easiest to continue his music education at a combined conservatory/university or college program, or at a university with an excellent school of music and a comp sci department. He can do comp sci in a lot of places, and it will be good enough. Music? That limits him. For the list you have, look at Bard, BU, Carnegie Mellon, Indiana, Oberlin, Rochester (IF he can do both Eastman and comp sci), St Olaf, Tufts but only with NEC combined program, Michigan. I don’t know enough about some of the others, but I do know that he should strike off the LACs that don’t have conservatories. Amherst and Wesleyan will not have what he needs for music. All the other LACs, unless they have a conservatory (like Bard and Oberlin and St. Olaf) will not, either.
Consider all of the combined conservatory/double major with college type programs. For my son, Yale/Yale school of music, and Columbia/Juilliard were on the list. They are easier on the combined major kids than is Harvard/NEC, which is also a consideration for your son, along with Tufts/NEC. Harvard loves its musical ensembles. If you can get your son to the attention of the conductor for the Harvard Radcliffe Symphony, and he wants your son, which it sounds as if he would, especially if his best percussionist is graduating in 2022, that would give him a big boost. A LOT of the kids with whom my son played got into Harvard.
What my kid, who was probably top 5% GPA good public high, 36 ACT, played in prestigious pre-college programs and had won a couple of big competitions, did was make a list of every school in the country that had a conservatory or a school of music. He eliminated the ones that did not have respected academic programs (like U North Texas, a powerhouse for his instrument, but not academically competitive). He eliminated the ones that he just would not go to (Baylor). Then he looked at the teacher(s) for his instrument. Did people like working with them? (Found that out through networking with all the older players he’d met, and talking with his teachers.) He listened to their recordings. Did he want to wind up sounding like them? Was the teacher teaching in four different schools all across the country, meaning spread too thin? Was the teacher sick, on a prolonged leave of absence and being covered for by rotating subs?Then he looked at how easy would it be for him to actually get to the classes at both the school of music and the academic school. All of these things really helped him to narrow down his list. He wound up with about 7 schools - BU, Maryland, McGill, UConn (in-state safety with fabulous teacher), Yale/YSM, Columbia/Juilliard, Harvard early action. He got into Harvard EA, took it, withdrew his other applications. He will probably continue studying privately, maybe try out for Boston Youth Philharmonic, and of course will play with Harvard ensembles.
So I would suggest that you show this to your son, have him start making a spreadsheet with all the things that are important to him. His interests may lean more one way or the other before November, too. For my son, it quickly became obvious which schools were the right ones for him, once he’d made that spreadsheet and done his networking research.