Exactly. Too many have been told by salespeople or forum experts that "ohh yes leather shoes and boots are supposed to almost hurt when new and they'll totally stretch to fit"Are you certain the 9D is not too small of a size? Please don't count on stretching to produce a proper fit, especially for the length. If your big toe is at the end of the shoe the shoe is too small. And a bit of heel slip is desired for a loafer shoe, not so much that the heel comes all the way out of the shoe, but a little bit of heel slip is a good thing,
In reality the length will never change and the width of the insole isn't changing, what's happening is the upper is molding to your foot although an incorrectly sized shoe or boot, especially a smaller than optimal one, will never feel good.
If your longest toes are hitting the end of a shoe or boot, it's too short, period. If your toes are getting squeezed together/held together by the toebox, it's too narrow.
Unlined mocs and loafers can and do mold pretty quickly but even they aren't going to get longer or a lot wider if they're too small.