First : Congratulate your nephew for me. What MOS is he choosing?
Second : I don't think he will have a chance to see an M9 in basic training - I agree with the above post , M16a2 most likely.
Third : If he isn't a runner now , he better get started
If you don't have an AR platforn , see if there is a nearby range that has one for rent. Most indoor ranges have rentals for customer use.
until that day,