Quote from TennisCoach on May 8, 2016, 11:57 am

Our son just turned 9 and is playing a

Babolat Pure Aero Lite with Tecnifibre NRG2 17 Strings (tension 52)

http://www.tennis-warehouse.com/Babolat_Pure_Aero_Lite/descpageRCBAB-BPAL.html

http://www.tennis-warehouse.com/Tecnifibre_NRG2_17_String/descpageACTFUSA-NRG17.html

So far it seems to be the best combination for good power and precision but he is playing really competitive as a USTA Boys 12 player in Florida. The bad thing is that the strings will last only 4 to 8 hours of playing which is quite expensive. Any advice for a hybrid that lasts longer?

But... this is for sure not a good combination for beginners at that age.

An interesting article from 2011 about racquets and strings used by USTA 12 players :

https://bigtimetennis.wordpress.com/tag/junior-tennis/

Quote from Ryan Rogen on April 19, 2017, 10:25 am

My son is a  beginner and I bought  Head Liquid Metal 8 Strung Tennis Racquet . One of my expert friend recommended it . This bargain priced racquet also has vibration dampening technology built into and a very generous head size too. It’s a great racquet for beginner and intermediate level players.It has a very generous sweet spot. There is no better feeling than to be able to slightly mishit a shot and still get a lot of spin and power on the ball.