Don't stress too much, micro ... placement of the round is what matters most. You want a pistol that feels natural in your hand, you can acquire the sights quickly, and you can control to deliver the round accurately. I prefer firing the .45 ACP out of the 1911 frame, but the Springfield XD-S is a lot easier to carry. So, if I am traveling ... it's the 1911 ... if I am going around town with it concealed ... it's the XD-S. For the 5-round magazines, I install finger extensions to make it easier to grip ...
The finger extensions are very easy to install. BUT, Springfield makes the XD-S in 9mm, too. If 9mm is what you are used to and are comfortable with, go with that and don't give it a second thought! The 9mm is far better than the .380 ACP (originally designated by the Germans as the 9mm Kurz - or 9mm short) and the .380s tend to be way too small for my hands, which is why I don't own one. The only reason I suggested them was because you mentioned an ankle holster.
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