No big surprise that this turned into your typical caliber war. However, for my take on your question only, here it goes:
No. I think Alan Fud put it best in his first post here. In quality loadings the 9mm is quite good. Ammo selection is very important w/ 9mm, more so than with .40 or .45, since there are some bad choices in 9mm ammo. However, today there are enough good 9mm choices that I am very confident using a 9mm, .40 or .45 for my defensive needs.
However, (and I am a 9mm guy), if I was you I would buy the .40s&w versions of the guns you are looking at. Why? Because you don't sound completely confident in the 9mm. If you need to be talked into it you aren't comfortable with it. If you aren't comfortable with it there is that chance that you just might hesitate a fraction of a second when you need to act most. If you are uncomfortable with a 9mm, for whatever reason, you should relagate your 9mms for range/fun use only.
As for recoil, yes the .40 is noticably stronger in felt recoil. The 9mm is a light but very fast round that gives a short, sharp recoil into your hand. The .45acp is a slow heavy round that gives a slow but strong push into your hand. The .40S&W is both (relatively) heavy and fast so you have a heavy recoil in a sharp, short shock. To me the .40 is a far less comfortable type of recoil than 9mm or .45acp. However, in guns heavy enough to handle it you will be ok. I don't know about the Kahr in .40 v. in 9mm. A buddy has the MK9 in (obviously) 9mm, a range had one to rent. It isn't bad at all. However, I have not fired a MK40 or K40. If I was to venture a guess though, I doubt that it would be tougher than a J-frame shooting +Ps.