Can't tell you how to set up a FF9, but, here's what I did.
1. Open up both elevator servos and fit long leads. (I used standard Futaba 3003's)
2. Reverse rotation of one servo by switching motor and potentiometer end connections.
3. Use a standard Y lead.
You can also do this by using a Y lead, an extension lead and an in-line servo reverser, but this has more plugs and sockets to worry about.
Dave :^)