how long dose it take for a cc to grow from fri to fingerlin

I certainly don't know the real answer, since I don't know how to determine when a fry becomes a fingerling. I'll leave that to the experts.
But, my 4-5 inchers grew into 8-9 inchers in two-and-a-half months this summer, in an open pond environment. Had I been able to keep them captive, and fed ever day, I strongly believe they would be at least 12 inchers by now. Maybe bigger.