Even as a head 6A high school band director, I and my two assistants were on 10 month contracts.
We did get stipends, however stipends can't legally go beyond a contract. I don't think any lawyer for the district could justify and win making band directors do 4th of July parades (and associated rehearsals) and summer band, no matter when it started before the legal start of our contracts, which was the first day of inservice...about a week before the first day of school.

With that said, we did what we needed to do. You could win the above battle, but you would lose the war.