What are some virtual worlds for a 9-year-old

The best virtual world for a 9 year old would be:
Club Penguin
Fantage
Our World, and
Panda Anda

--but Club Penguin and Our World are the best :)

You should try toonstunes.com. It's a fun virtual world where you can chat with friends, dress up your avatar, decorate a home, play games, and create totally original music! So check it out :) I'm a moderator on the site and I think it's really fun.