Do they ever turn down volume in certain daytime showings for kids?

I've asked them to and they have accommodated

I used to work for this theater, and also others. If the volume is not right, notify theater personnel. They'll walk inside and assess the situation and fix it if it's way off. If it's not noticeably off, it might just be your personal preference, but they'll likely make a small tweak (unless it's already too loud and you want it louder, or vice versa).