A great conversation piece. Lots of history went into them. Yes, they once fed the world. I know an old man who once owned several truck farms. He had several 9N &2N, said they were perfect for that operation. I think they are not used today for their intended purpose. Those of us who want a loader, maybe a little backhoe, plow snow, cut grass, bush hog, grade the driveway, skid logs, etc. etc. I believe could do better. In my world the "61 B275 IH gets used to power the wood splitter, hog, or grade the driveway. The '85 IH 385 gets light duty loader work, hog, etc. These tractors are twice the power, weight, features, and cost the same, on half the fuel.
Still the bigger jobs like earth moving, and tree work are saved for backhoe, crawler, or Power Wagon.
One thing I'd retrofit the 9N with would be wheelie bars. These tractors have killed a number of people when they were either hitched improperly, or a component of the three point hitch breaks. They are famous for going over backward. A very experienced friend had a real close brush with tragedy loading one on a trailer. When it went up on its drawbar, he had the presence of mind to push the clutch. The landing wasn't graceful, but he was alive. The antique tractor pulling rules disallow their pulling with the three point drawbar, likely for this reason. Low center of gravity is this tractor's best feature, but it places the drawbar (if at standard height) too high. The tractor can walk out from under its drawbar.
Willie