If money is no object, and he wishes to move up to centerfire steel matches, then http://www.stiguns.com/the-sti-steel-master/
If he gets heavily involved (high round count training) then there is the rare possibility of stress fractures in the wrist. A compensated gun will mitigate that.
I disagree with kraigwy on the 92fs - I use it for newbies and kids training as its a very forgiving gun, but the double action is long and heavy and not really suited to small hands. USPSA & IDPA will require him to start with the hammer down. If he is after a 'service' or production configured gun, then the CZ75 SP01 Shadow would be my pick. Steel frame, accurate, relatively inexpensive, DA/SA. He can shoot it in single action until his hands are fully grown and compete in Limited with minor power factor loads if he desires. When his hands are big enough to crank off rounds in double action then it will be very competitive in USPSA Production. I don't know if it meets the restrictions for IDPA SSP.
FWIW my background is as a former IPSC PD competitor. I was selected for the Australian team once upon a time. Back then 8 out 10 top Aussie PD shooters shot Glocks. The year after the Shadow was released it was 9 out of ten shooting Shadows.