Anonymous wrote:OP, people are weirdly piling on you. Obviously there aren't tons of 10th grade spots, but, schools also want to fill them.
I'd call admissions and ask how many spots they anticipate and let them know you are very motivated to move your kid and be ready to articulate why your kid wants to go to that school. Ask if they offer interviews. Sign your kid up for shadow days. Go to the open house. Have a unified articulate response for both parents and kid in case they want to do interviews. I'd also use any connections you might have (do you know teachers/board members/administrators at any of these schols).
It really depends on where OP's son is applying. Sidwell, STA, Potomac generally fill any 10th grade spots with athletic recruits. I have kids at one of these schools and all the 10th grade spots the past year went to elite athletes. A friend applied to another and they were basically told the same thing by admissions.
These school don't "need" to fill the spots to pay the bills. They use them to strengthen the sports teams OR to sometimes take a VIP's kid or a transfer from an out-of-town private. It is what it is.