All those saying that the girls might not want to eat must not realize how hungry runners are after practice. If there's one group that can out-eat teen boys, it's runners!

OP, even if the girls are eating at the picture house, you'll want to have something for them as soon as they get to your place after practice. I'd include some protein along with "fun" snacks.
You've already received lots of good advice on items to have on hand. I don't remember if anyone mentioned hair spray, but if any of the girls are doing some kind of updo they'll want that. Also, make sure you know where your fuse box is and how to re-set it - we learned the hard way that 2 hairdryers in the same room tripped ours!
Along with your sewing kit, have an iron and ironing board ready, in case anyone's dress is really wrinkled. You can either use the steam function to steam the wrinkled section, or have a cotton pillowcase ready to lay over the dress as you iron. You never want to iron directly on the dress.
Have fun! I'm a couple years away from high school with DD, but she and her friends got ready for an elementary school dance here. They were so cute, and I even ended up curling one of her friend's hair for her. I hope your daughter has a wonderful time!