I may just be lucky, but I had a mixed box of 115gr WWB, American Eagle, old Lawman FMJ and some old 147 and 124gr ball ammo that I decided to put through the pup on my second range day with the R9. I just mixed them up in the magazines rather than separating them by type just to aid in my own training.
I've also fired about 100 Gold Dot 124gr and a couple of mags full of Hydrashoks through it. All, including the mixed box, without any failures. They were all standard pressure loads of course.
It seems that at least this particular R9 is quite indifferent about what ammunition I use.
To answer the original question, I thought I had seen standard pressure, short barrel Gold Dots, but I can't say what caliber they were. The +P are obviously not to be used in the R9, as per Rohrburgh's specs.
Edit:
http://www.speer-ammo.com/ballistics/ammo.aspxThe only GD SB available in 9mm is 124gr +P. It must have been the .45 ACP I shot as standard pressure in my PM45.