Need help for Mac (again!)

All my settings for Norton Online Family are correct and up and running.  I have Firefox 9.0.1 running.  No websites are being blocked on my son's account.  Do I need a plugin for Firefox?  If so how do I get it as it does not automatically come up when I start Firefox.  Am I correct that NOF still does not work on Safari 5.1?

 

Thanks in advance for any help!!!

 

Wendy