Big Rod , Big line , Big Fly = Big Leader ! Tapered furled leaders turn over very well on my 5-6 Wt rods. And the leaders are made for the WT. If you can get a 9 WT tapered furled leader I am sure you would be happy with it. But you can expect to pay somewhere around $30.00 for it ! Some of my 5-6 Wt ones are around $ 20.00
Good Luck , Let us know what you end up with. I am going to go after them also with a FR someday soon !