AOL 9.0 offers you the option using the firewall in 9.0

You can view your settings by clicking "view safety status" from the sign on screen. I do not use their optional firewall and Limewire is running fine alongside of AOL 9.0. I think I have had every beta version of AOL 9.0 installed over the past few months without any issues.

I do use a router and Norton Internet Security without a hitch.

I don't recommend you go without any firewall but I do think AOL's firewall (powered by McAfee) is better left off. AOL 9.0 is trying to do too many things without doing much of it well and often without the user having the option of choosing.