Learning Useless Rules

This weekend, the shorter of the short people had his first baseball tournament in which the infield fly rule was part of the game. If there are base runners on first and second base with less than two outs and the ball is popped to the infield, the batter is automatically out. This is because it is a situation in which the runners find themselves in a dilemma. If they run, then the ball gets caught and the player who caught the ball can throw to the vacated base for a double play; but if they don't run the infielder can intentionally drop the ball, pick it up and throw it to the base to which the runner would have advanced and start a double play that way. To stop this sort of double play by cute strategy instead of skilled play, the rule was created calling the batter out and allowing the runners to maintain their positions.

On the one hand, no nine year old will understand the situation well enough and have sufficiently skilled fellow infielders to turn the intentionally dropped pop-up into a double or triple play. The rule does not serve its purpose in this game. On the other hand, the rule will be part of the game in years to come, so the kids need to understand it as they grow in the game.

Does it make sense to have the infield fly rule for nine years olds for whom it is a useless rule?