Replacing the front tires on my '41 9N. Can these tires be tubeless?
Looks like a solid front rims. As long as I replace the valve stems for
tubeless tires? Looking for tires, the junkyards I have talked to never
heard of the standard measurement - 7.50 X 16. The closest equivalent
is a 225/90 - 16. Just wondering if anyone has gone this route.

The optional wheel for the N's was a 6.00 x 16, not 7.50. Most folks installed them when they had a loader installed.

Yes, I have a dearborn loader on the front. I gather they are oversized for that reason.
I ordered a 6.5 X 16 10 ply tires and tubes.

I had a Wagner loader on and off my (dad's) 1951 8N from about 1958 to approximately 2015. We did a lot of work with it over the years, but it would interfere with farming activities so, off it came until we needed it again. I couold get it off in about 1/2 hour and back on in about 45 minutes.
We had put 6.50x16 6 ply tires, with tubes, on it and pumped up to 50 pounds.
In 1985 we built a new house and I moved about 1400 yards of wet clay as a back fill. Be prepared to have sore arms. No power steering? Armstrong!
Also be careful to not raise the loader too high with dirt and on uneven ground. The standard Wagner bucket full of dirt could lift loaded rear tires off the ground, particularly if you hit a pothole.
Lastly, know that many N front axles broke and drove them up through the radiator and water pump. On a 9N it could also take out the distributor.
Looking back, I don't know how I never had that happen. Very lucky.

Check Tucker Tire or ME Miller Tire. They have the right tires. The rims are not made for tubeless tires.

I got tubes and tires ordered. 6.00 X 16