I play on the hive and I would say, it is a very great comunity.
The hive doesn't have any cussing or anything, the only thing that might be a problem is the minorly competitive minigames that have very very mild violence (I am only including this at all because some parents are very overprotective). Other than that, the hive is suitable for an eight year old. Although the hive is a family friendly server, there are some servers out there that have cussing, griefing (vandalising), and even racial slurs by the users themselfs when the owner isn't on to stop them. I would check the servers that your son wants to play on before he goes on and just watch the chat for a minute or two and you should get a feel for it.
I hope my answer is helpful