mjt,
I carry my R9S in the pocket, but did carry a Kahr PM9 IWB, so the experience would be similar.
My favorite holsters come from Milt Sparks. I used their EXecutive Companion for the Kahr pistol.
Their big seller just might be the VM-2. Also, the Summer Special 2 would be a fine choice.
Since your shirt might be un-tucked, please also consider a belt holster. I have the 55BN on order right now for an HK USP .45 full size. An R9S version could keep the pistol up rather high, and you would avoid the discomfort of having something inside your waist band.
It would still be hidden by the untucked shirt. Milt Sparks could gladly suggest which holster keeps it up high. I think it would be the 55BN. Other makers have a model which is similar to the one made by Bruce Nelson, hence the name 55BN.
Meanwhile, once a decision is made to avoid the pocket, many shooters prefer a more powerful weapon.
There is a wait of typically 12 weeks.
Bill