3bus:
First of all, welcome to the Forum, and congratulations on selecting what I consider to be the ultimate in pocket pistols. That is one fine birthday present from your husband!
And here is wishing you a full and speedy recovery from your forthcoming surgery.
The heel magazine release on the R9 should present no problem. This pistol is not intended for competitions requiring speed loading, and a speed load is also usually not required in ordinary personal defense situations (God forbid you ever have to deal with one). Even so, with practice, you will learn to manipulate the R9 magazine change faster than you may now imagine.
As for a SmartCarry holster system, I tried one when it was known as the "Thunder Belt" but didn't find it comfortable. Some others, however, swear by them. I think it's just something you have to try to determine how it works for you.
Welcome again, and good luck!