I found a picture of the back of the 909 and it does look as if all you have to do is get the plugs out of the center of the binding posts, as Geared4me suggested. I've at time had to resort to drilling a very small hole into the center of the plug to give a place to get a small screwdriver tip into the plug and work it out.
If you accomplish that, the BFA-style banana plugs that Reubent suggests are the way to go. A good option in addition to the Nordost Z-plugs are the Audioquest plugs.
If you accomplish that, the BFA-style banana plugs that Reubent suggests are the way to go. A good option in addition to the Nordost Z-plugs are the Audioquest plugs.