I would look for openings that don't lead into trouble right away, lead to positions that are simple enough to be understandable, and if possible give opportunities for tactics, since that's what they should be concentrating on.
Recently someone said his teacher suggested the Four Knights, 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6, and that seems a fine choice to me. Both with 4.Bb5 and with 4.d4.
Traps? Why?
I run a junior school chess club - ages 7 to 11. I'd be grateful for any suggested openings, opening traps etc which are simple and easy to remember for youngsters. Thanks.