Trying to find a ferry from Catania to Naples and cannot find anything for Sept. Has anyone taken this trip?
Why not fly? Lots of cheap options on whichbudget.com. I don't think that there are any ferries that do that route: http://www.thinksicily.com/travel-to-and-around-sicily/car,-sea-and-rail.aspx For lots of good info about Sicily post your questions on Trip Advisor.
Ferries ply the Palermo-Naples route. Sicilian stops include the Aolian Islands, ie. Lipari.
The ferry from Catania to Naples is operated by TTT Lines.