No option is horrible for every family. You've got to look at how he dealing with what must be a difficult situation. If afterschooling can become a tradition in your lives, that is a good thing. It would be nice if we could teach our children to self-enrich, and I'm sure some kids would get the hang of it.
DS11 is missing his friends a bit, and wishing that he had been more willing to self-enrich and afterschool, but he just wasn't there back then.
Good luck with the meeting. You don't have to agree to anything right then, although the pressure will be on. Remember to keep your doubts for this forum, and act focused and confident. It is the responsibility of the school to find a way to teach at his readiness level. It really is!
You can offer to sign a release that you will be responsible for any emotional fallout from the skip - that helps some schools feel less chilly on their posteriors.
Good Luck,
Grinity