l_elieze:
First of all, welcome to the Forum and congratulations on your purchase of the R9.
The problem you describe could be due to some break-in "dreck" (an aluminum shard, a piece of brass, or grit) becoming lodged between the slide and frame of the pistol. I don't know how well the pistol was lubricated before the first range session, but if it were dry that could have contributed to the problem. Also, if the 30 rounds were fired in rapid succession, the new pistol may have become overheated due to its minimal tolerances.
I would try lubricating the piece liberally with a penetrating gun oil, letting it sit for a few minutes, and then gently trying to free the slide. You might want to use leather gloves or a flexible rubber friction pad (the kind used to help open Mason jars), since the gun will be slick with oil. Just don't use too much force. Patience and an easy touch should do the job.
Good luck, and let us know how the problem is resolved.