You don't have to lead players along by the nose - open-world games are surprisingly attractive even to kids (maybe especially to kids, who haven't yet been conditioned that everything needs to be structured with explicit step-by-step goals).

When I was in high school I did a lot of volunteering at the local science-museum where we had terminals set up with the Incredible Machine. They were always occupied.

Kids have an innate love for exploring, moreso than adults. We beat it out of them later, but in the mean time open world, unstructured games are some of the best ways to teach things to people. Look at SimCity, Incredible Machine, etc etc.