BRAIN POP has a great video to remember September 11th in a child-friendly way. It is not too graphic (it is still a cartoon) and recaps what happened that day, as well as attempts to explain why something like that happened to the United States.
BRAIN POP also has a few more related topics that might help students understand some important current-day events related to September 11th: War, Terrorism, and Airport Security.
Enjoy implementing technology into your daily lessons!