This bat would not be approved under the new USA Bat Rule standards used in Cal Ripken and other Little Leagues. When it comes to wood bats, only bats made of maple, ash, and birch seem to be allowed, while bamboo, composite wood, and other blended models are not allowed. You can find more information at LittleLeague.org.
The best color of Lizard Skins grip to use on the BamBooBat Bamboo Wood Youth Baseball Bat: HNBBY Natural/Black is strictly one of personal preference.
The correct size to get the BamBooBat Bamboo Wood Youth Baseball Bat: HNBBY Natural/Black for a 9 year old would be determined by a player's height and weight as well as the weight of the bat they are currently using and how well they are able to handle this weight. Please refer to our bat coach feature to get a better idea of the correct length at: http://www.justbats.com/bat-coach/