I would not use a freewheel with more than 7 cogs. The extra long axle, excessively dished wheel, etc, will cause problems. Get a 9 speed cassette hub and rebuild the wheel.
That's the response I was hoping I wouldn't get.lol. I had hoped it was one of those things that is sketchy in theory, but lacks any real problems in practice. I guess it's time to stop being cheap.