See what size feeler gauge will pass without effort between the slide and frame directly above the forward end of the trigger guard where the camblock is. A clearance of .020 is absolutely normal, and your gun is tight. You can squeeze it down within that amount, but it certainly should not lift, being in upward compression and preloaded by the guide rod assembly (spring). You cannot compare the axial movements of an SR9 to an SR9c directly. The pin through the camblock is the pivot point, and the farther you get from that point, the greater the apparent swing will be. Thus, the shorter slide will have less end movement, even with identical clearances at the camblock, and may appear more rigid, even though it is not mechanically. The SR9c differs in ways that go beyond simply bobbing grip and barrel.
Be sure the CAMBLOCK (part #28) is tight and that the camblock pins 52-53 are installed correctly. Those parts require no removal under normal circumstances. The rear of the slide has about the same amount of play, except with freedom up and down, and there must be some side to side play. Together, the X & Y axes play will allow some rotational play. The accuracy of the gun is, as one previous contributor mentioned, a function of barrel-slide (bullet axis to sight plane) battery, and has absolutely nothing to do with frame-slide battery.
Please. Don't get crazy kicking tires and comparing belly buttons. I've seen folks shake a gun this way and that to see if they hear anything. They push and pull to see if things move around and get distressed if they feel any wiggle. Of course they will. If they didn't, they wouldn't function reliably under all conditions, which is essential. The SR9 series should feel pretty snug when in battery, with the aforementioned clearance, but there are tolerances built in and required to assure function. I know from personal experience that SR9s shoot like crazy, and are extremely accurate.
Let me make a note about Ruger with regards to tolerances. The word "tolerance" in the machine industry has changed radically since CNC machining and the use of investment casting (lost wax process) as used by Ruger. It is not a bad word, and neither is it the fudge factor it was in years past. Where tolerance used to be a min-max dimension that any given part was allowed, some guns would come out tight, average, and loose, depending on the combination of parts assembled and the fitter's ability to obviate the combined tolerances by his/her skill. That is essentially a thing of the past, thanks to CNC and precision castings, and has been so for a very, very long time with Ruger. While not without error and even some variances involved in those processes, coupled with human interplay, it can be reasonably stated that each Ruger is the same as the one before and after it. If you believe something has gotten off kilter, call Ruger, and they will gladly make it 100%.