The 40 is not only snappier than the 45, but it sort of has a little twist to it as well that can be a real pain. As said, the 45 tends to have more of a level (but a little heavier to me) push back. You have to figure in grain count too.
The 9 would be easier overall and of course, the heavier the pistol, the better off you typically are recoil wise, regardless of the load. I realize that if it's for carry, you don't want a forty ounce gun!!
This is a good site for a number of comparisons, including recoil--just enter in a handgun and among other things, it will tell you its typical recoil as measured:
Genitron.com - The Handgun Information Resource - Home Page
Looking up recoil and comparing, there are some guns that may surprise you, although physics is the ruling factor overall--the greater the mass, the lighter the recoil
tends to be.
It also depends on where your arthritis is. If it's pretty much just in your fingers, the difference might not seem as great between guns. If it's mainly in the top of the hand in the area between the wrist, thumb and 4 fingers, the 40 would probably be a pain, as mentioned, arthitis typically gets worse and can vary with the weather--I know personally!.
Some of the newer 1911's are quite accurate and a heavy full sized one with a reputation for accuracy might warrant consideration. I'm not talking Kimber or Les Baer prices either.
With the advances in and the variety of 9mm ammo available today, I wouldn't dismiss that round too quickly. For target accuracy and for critical self defense with the right brand, 9mm ammo is pretty potent stuff---9mm doesn't have to 'zip right through' a target any more--I think it got a bad rap a while ago and doesn't really deserve all the negatives.