Because of the extremely large developmental range covered by the Active Start stage of the LTAD the amount of sleep required throughout this stage varies greatly. It also worth noting that the amount of sleep required varies between individuals.
The following links point to resources that have been collected and are relevant to this skill (?).
Sleep, Recovery, and Human Performance, is a 20 page pdf document put together by researchers in Calgary for Sport for Life. It discusses the importance of sleep and recovery for sport performance and some of the most prominent sleep disorders and factors that affect one's sleep and recovery. The document is very clearly and consisely written to discuss the key factors across all LTAD stages.