The CFL is the newest - and so they say - most exciting 9x9 Football simulation in Second Life. The first ever season is about to start and you can still be a part of it. The Ohana Packers are currently recruiting new players and both men and women are welcome to join. And the Packers are also recruiting Cheerleaders. If you are interested in become part of the American Football community in Second Life, you should contact Mal Galaxy in-world. Or you can contact the team on Facebook.
Playing a team sports in Second Life gives you an experience that you can't find with typical console game franchises: you need to learn coordinating your action with all the other human players. Unlike in the console games, you really need to learn tactics and develop a good team play with your mates or you and your team will not stand a chance.
I also found a video on Youtube featuring a 2012 VIFL match of the Packers and it shows the typical Second Life Football game mechanics quite well (if you skip the first 30 seconds). It looks like fun! Go Packers, go!