Don't forget to pack an extra change of clothes in a ziploc (stays in the locker all year), lunch, a water bottle, all those forms, and the items from your school supplies list.
The first bell is at 9:25, but get there early - it will be pandemonium on the playground with all the extra parents milling around. Find your classroom line, leave the backpack there, and play until the bell... then kids have to come back and line up to go inside. Usually, kindergarten parents can go inside on the first day to help with locker finding and so on. Don't forget to take photos (it's tricky with all the activity).
The annual flag raising ceremony will be around 9:45/10 at the front of the school, so stick around for that.
Pickup is at 3:30/3:35 in front of the school. Only K-1 classes are picked up at the front of the school so it won't be hard to find them; usually they are on the lawn approximately in front of their classroom. Children must wait for parents and teachers to make eye contact before leaving the class group, so try to enforce that right from the start.
Congratulations! You've made it!