Yes, 9mm is effectively identical to .45.
And it isn't "in my mind." This isn't really "my" info. I am passing along what I have read and learned. It's based on all the statistics, knowledge, and science we have on the topic today. Dr. Mahler (sp?) gives a great lecture at GCL from time to time; he is a brain surgeon and firearms enthusiast, and he seems to think 9, 40, and 45 all have the same impact on the body and the same chances of stopping someone. All the statistical reports I read about real world gun fights tend to look the same regardless of how big or heavy the bullets were. When I hear the same thing from Massad Ayoob and all the other credible authorities in the industry, I tend to believe them. The only people who seem to say that .40 or .45 have more stopping power seem to be people who did their research 10-20 years ago when that was true, or just people who own guns in those calibers and want to feel good about said ownership.
And for the record, I'm not saying the recoil and capacity differences between 9mm and .40 are minor, I'm saying even if YOU think they are minor, why accept even minor challenges if you don't have to? Me, personally, I believe that .40 is significantly harder to shoot that 9mm, at least out of the guns I have fired it in. That's not to say its hard, but more that 9mm is very easy.