Paul, I think I understand where you're going here. I tried making /Volumes/Data/OOTP9/OOTP9.app/Contents/MacOS/OOTP9 executable by running "chmod +x OOTP9". That worked. I am now able to load OOTP9 successfully.
However, now I get a message that says:
The game continues to load, then I get this:
When I hit OK, the game closes. Remember, this is when I do a custom install location. I'm guessing that's related because it works OK when I install to the default location. Except for the whole no multiuser support thing.