Andy, sorry to read about your Uncles' heart attacks. Hopefully they pull through and all will be decent.
As for your batch of engines you hit the motherlode. You said above that you got FOUR TeeDee .010's in this batch of stuff. Each of those is worth from $70 to $120 per engine depending on condition. So the price you paid was pretty much a gift price for you.
With a regular size Mach None or even if you blow it up by 15% to suit the .09 there will be nothing at all calm about how it flies. The performance of the TeeDee .09 will see to that. Cox may have sold these engines with a throttle attached but as I recall the "idle" was a bit of a joke. And I've seen enough reports about extremely poor throttle transitions on any RC Tee Dee engine around here to realize that these are engines best used as "pedal to the metal" options with the carb as more of a cutoff on demand sort of control.
In any event bolt that sucka' to a block of wood and ground run it to get an idea of what it performs like before you consider sticking it into a plane.