Exciting thread that reminds me of exciting times. Back in the 90s I participated in an initiative to teach Go in schools. One of the kids we initiated to the game went all the way to become the French champion 10 years later.
Kids are very competitive, and providing incentives was key to keeping a core group. Having other schools to compete against was also a big factor. In our case, we found a sponsor and were able to organize a tournament, with a trip to Japan as first prize. You might find a local sponsor (company or game store) willing to provide some support. Good luck!