A friend of mine has this problem. I haven't seen the wheel, but I suppose that the broken spokes are in one "area". It's a 27 inch wheel.
Is there any tool that can hold hub tight enough to use a freewheel wrench?
Unless its a super low spoke count wheel (16 or 20) then it should have 32 or 36 spokes. 9 broken ones is totally unrideable, but the remaining spokes should be okay to get the freewheel off with a vise and a freewheel tool.
Depending on what killed 9 spokes, the rim may be unusable, and at some point your wallet is better off with a new replacement wheel.
This one is way easy. Use a pneumatic impact wrench. There is very little torque transmitted. Bruuupppp and its off. I use this a lot with my single speed spin on cassette with the torque from Hades. When I did this manually, I needed a six foot breaker with wheel tied down. Impact hammer is awesome.
No vise. No marks on part. I would just hold hub carefully with work gloves. Heck, bring it by my house, we'll have it off in 30 seconds.