I have a feeling that the kid's frustration has less to do with deviating on move 11 in an open Sicilian than with not getting to play 1. a4, 2. Ra3, for example.
Chess 960 isn't going to change that. Plus I bet a player would have only a minor effect on his rating (the improvement might be slower) from playing 1. a4 any except 1.. e5 or 1.. e6, 2. Ra3 every game.