Quickstart tennis regulations

How slow is too slow? The newest USTA trend is to scale down tennis for younger kids. Some of the regulations include using smaller racquets, orange green dot or red balls and playing on shorter courts. While I see that there are benefits to this type of structure for certain kinds of kids, I wonder can things be too slow and too small for some kids who still fall into the ten and under category? My team competed in the 10 and under junior team tennis playoffs. During this tournament a regulation was in place where everyone was required to use a racquet that was 25 inches or less. Yet, this regulation wasn't reinforced throughout the season and many of the kids who are on the older, taller, stronger end of the spectrum play with 27-inch racquets in their practices and matches. One of my students was particularly perturbed by having to use a 27-inch racquet. It was evident that she was having a hard time because the 25-inch racquet didn't afford her the power she was used to with the 27-inch racquet. Another coach told me that one of his players was naturally powerful had a hard time adjusting to the smaller court. While I do see the benefits of using orange or green dot balls for learning to execute strategies such as serve and volleying, I wonder if for some kids there isn't a point of playing on the smaller court. After all, once they hit age 11 they will be able to play on a larger court with yellow balls. So why waste a year making artificial adjustments to your game? I think some kids feel the need to hold back and not fully utilize their power and then are hurt when they play higher age groups and push instead of hitting through the ball. But, is playing 12 and unders at age 9 the best alternative?