I trade E$ Futures also. Here is how I would imagine you would go about it. I'll try it on paper later... I believe, similar to above poster says, you can use the spot rates to directly relate, hence synthetically trade the 9-month libor rate.
This is a clarified version of an equation taken from the CME website, you can see that you can calculate the 6 month spot rate, which is essentially the 6 month libor, from the 3 months forward rate (100 - E$) and 3 month spot.
1 + 6 months spot rate * ((Days Remaining to 6 months expiration)/360) = (1 + 3 month spot rate * (Days Remaining to 3 month expiration)/360) (1 + (3 months FORWARD rate)*(Days Remaining to 3 month expiration)/360)
So from reorganizing the formula, I believe you should be able to grab the 9 month libor from the E$ rate...