Your weight will be ok. I have a VQ p-40 at almost 11 pounds dry(saito 100) and it flies fine and has a bit smaller wingspan then your D9. With flaps, it lands ok.
Also have a fiberglass Kyosho corsair at 58" that weighs 10.5 pounds on 6s. Flies great, but it does land hot because it doesnt have flaps.
One last note.....I rechecked what was on my graupner d9 and its actually the Tacon 110 from hobbypartz. It has an 8mm motor shaft so can use the e-flite prop shaft adapters I mentioned above. However, the Monsterpower 110 has a 10mm motor shaft so it cannot. I appologize for the mix up.
Right now, hobbypartz has the tacon 110 on sale for $44.
If you can get a spinner that isnt bolt thru the middle then using your monsterpower110 will still work. Or you can talk to tru turn about getting a prop shaft adapter for monster's bolt on propshaft adapter in the kit. It is probably 12mm, while the motor shaft itself is 10mm. Ive done that before I think. They just want you to mail the propshaft adapter to them to get the pitch right for the shaft adapter used to screw onto the the existing one to run a bolt thru spinner.