People often recommend a value priced IWB holster, all of which are probably fine holsters. But I would rather walk around with a 30-30 lever gun all day than wear a handgun IWB. Of course I live in free America where the 2A abounds with the full support of the people. Plus I have a metal shield in my wallet so perhaps I am less concerned about the bulge that might be produced from OWB carry.
I have a ridiculous pile of M&P holsters, so when I first bought an SD9 & SD9VE I spent some time finding one that would fit perfectly. Some do, some don't. My G-codes were a no go, as were most custom kydex. The Safariland 7377 was a pretty good fit once tightened up. The ALS system retains the gun but still allows for an ultra slick draw. But the BEST holster I found for the SD9 series is the Bianchi 75 Venom. Fits the gun like it was custom wet molded to it. Mine is very well made, holds the gun very tight to my body, has the best thumbstrap I have found on a leather holster and draws nice and smooth (and re-holsters easily too). After a week or so of trying out the Venom I stopped looking and ordering a second one for my other gun.