volleyball is a late sport and not very friendly to little kid. In my opinion, it is better to attend clinic first. Depends on players's experience, e.g i9 runs clinic year around, while there are mostly beginners, it is perfectly fine if you just get started. Many club runs clinic/camp too and it is a good choice once you knows volleyball a little better. Btw I noticed all clinic/camp we went, it is mostly girls.

I suggest that you try either a Gaithersburg league or a Montgomery County league (Montgomery County also offers clinics). Don't expect to learn a lot, but you will figure out whether your player enjoys the game. If you are willing to pour more money into this, you can look up what the local clubs offer. Club offerings come with better quality coaching, but are available less regularly. Most clubs are focused on girls, but some accept boys (they can play on girl teams on regional tournaments up to 13).

Any recommendation for where an 8YO beginner (boy) can learn and play volleyball around Rockville or Gaithersburg?