Can I do ROTC if I have been released via medical board (for shoulder instability) and have a 10% VA rating?

ROTC is a challenge to get through medically, the answer is yes, but it will take some time and patience getting the appropriate medical evaluations and waivers if required.

First, and simplest answer, if talk to a recruiter. It's a pain to get a waiver, I know from experience as I'm still trying to get one. It has to go through the Surgeon General. Get documentation if it is better, or does not affect your ability to perform. And make sure it's good documentation. You'll need as much ammo on your side as possible.

If you can pass a PT test and have recovered most of your range of motion you should be able to. I herniated 2 discs on my first deployment and had problems doing sit-up and went before a Medical Review Board. Before the board met I deployed to Louisiana for Hurricane Katrina and the board determined that since I could spend hours wearing my helmet, vest, weapon and ammo and could shovel debris that was similar to anything I would do on a deployment so they let me stay in. They gave me a permanent profile on sit-ups and the run and I later deployed to Iraq and had no problems