Make sure you are focusing appropriately on the option you have. In our case, it was the LPS. DS had to go to orientation there, pick classes, etc. We kept emphasizing that this was an option we needed to consider, acceptances or not. This all happened pre- M10.
The vast majority of 8th graders are not applying to private schools, and they are looking forward to high school.
If you don’t get in, you’ll throw yourself into the option you have. You can reapply to BS next year, possibly expanding your list, possibly as a repeat 9th grader - or stay put.
One step at a time.