Hi JoHubb,
Although I don't have this particular aircraft installed, I never had any problems with aircraft in FS9 under Windows10
When you install FS9 in the default C:\Program Files (x86) directory you will run into the usual problems, that you required administrator rights to make any changes. In general not a huge problem, but just annoying.
The only problems I ever had with FS9 and Windows10 were all related to graphics. Especially the early versions from W10 didn't work very well together with the Nvidea drivers. And every Nvidea update and W10 update more or less caused problems. However this seems to be solved, as I can't recall I had any problems in the last two years.
As said I don't have Milton Shupe's DHC7 Dash installed, but I have a huge amount of models installed, including several by Milton Shupe.
Cheers,
Huub