I live not in a warm climate, but in the HOT & humid southern Florida swamps where it rarely gets out of the 80's even in the "cold" of winter so deep concealment is the only way to go and the MK9 is the smallest, serious-size gun out there (I originally carried the MK40 but found that to be too much of a handful to shoot accurately because of it's small size).
I've been carrying a MK9 in an inside the waist belly band from
ActionDirect. Even with a tucked in shirt and tight jeans (gotta lose weight), the gun completely disappears from sight.
I've fired it with hot Cor-Bon rounds and while the kick is snappy, it's manageable -- a whole lot more manageable than the MK40 was with hot loads.
Just one bit of warning, even though the gun is stainless steel, it tends to rust. I've been carrying mine for only about half a year and I've already starting to see this happen. Of course, part of the problem might be because I wear it 16-18 hours a day, 7 days a week.
In any event, I'm going to have
Scott, McDougall & Associates apply their special clear GnomeKote matte finish to the gun which is suppose to exceed the ATSM [American Standard Materials] 177 specifications for salt water corrosion resistance by more than 4000% (or something along those lines) but not chance the appears of the gun as it will still look like the original stainless steel.
Good luck & congrats on buying a fine gun.
Share what you know, learn what you don't -- FUD