The ballistics insert is a damn good idea.
That aside. (for the ages mentioned)
1) Any needed medications (but in child-proof caps)
2) Favorite snack items that keep
3) A couple of dehydrated meals they will eat (like mac & cheese, etc.)
4) Water bottle (metal)
5) Video Game, extra batteries
6) Coloring Books, crayons
7) MP3 Player, favorite songs
8) Survival Whistle (and know when to use).
9) Small First Aid Kit (soapbox size)
10) Emergency Blanket (mylar)
11) Emergency Poncho
12) Flashlight, batteries
13) Light Sticks (to tie on his/her backpack, so you can keep track of them)
14) Small, durable toys (think Hot Wheels cars, small figures, etc.)
15) Any comfort item (blanket, favorite stuffed toy, etc.)