Bo, I have taught knife safety several times to 11-13 year olds. Stuff I would hit:
Basic safety and etiquette, ie, blood circles, cutting away, sheathing/closing, proper hand off
Sharpening. Whet stones, dry stones, files, etc.
Storage: dry, out of reach
Different types of knives for different purposes
Different things cut and techniques (wood different than vegetables different than flesh)
More complicated stuff you could get into could be skinning, fileting, carving, etc. The most important thing the kids can take away is that a knife is a tool that can hurt you and possibly kill you. Probably one of the best lessons a young kid can learn from knives is seeing what they can do. I have seen people cut by knives many times (no, not after my teaching them safety), and nothing will instill safety better than watching blood pour down your buddy's hand after making mince of his finger. But try to avoid that teaching strategy.