The Pet Shop is a room in BeyondCP. You can access the Plaza from here. It leads to the Pet Shop Rooftop as of Puffle Party.
It was confirmed on March 1st that the Pet Shop would be in construction at launch and would finish starting at Puffle Party. Puffles could not be adopted at this time, and Puffle Launch, Pufflescape, and Puffle Roundup were all closed.