Yup. My Goldberg 300 is closer to 12 pounds with the smoke system, gear replacement and repairs, and tail reinforcements for the three servos.
It flat out screams with a 1.08 and 16x6. I can't "fly" it at full throttle... generally run it a little above half throttle for straight and level flight.
If I were to do it again, I'd use the .91 (or a 1.20). At the time I built mine, the .91 and 1.08 were the same engine block, so the 1.08 was a touch lighter. Today, with the FX series, the .61 and .91 are the same block, so you're looking at a significant weight savings, and still more than enough power.

My buddy built a Goldberg Ultimate, but decided to cover in Solartex and then paint it. Three coats of primer and two coats of paint plus a clear and it ended up at 14 pounds. Flew like a brick with an old OS Max .80 (dual glow plugs!). He dumped that for a Magnum 1.08 (ABC, OS is ringed) and it now has unlimited vertical. The Magnum 1.08 swings a prop 1 inch smaller than the OS 1.08, so I'd guess that the FX .91 would be comparable in power to the Magnum 1.08