"Ron Rosenfeld"
They are probably saying "clearance on request" which means that they have
called ATC and requested your clearance. So yes, waiting for them to call
you back is proper.

Yep, what Ron said. It is non-obvious terminology for the pilot - maybe
controller obvious. But it's one of very many that you just get to know
after awhile.

I usually get "on request" and I know to just sit tight until they call
back. Usually leave me sitting on the ramp. Next time they do it at
Westchester, I'll shut down.