Feeding it lots of goodness from the compost bin has given it every reason to grow strongly, as you've seen, with no reason to produce flowers.
I'm with Goodlife re. potash since potash promotes flowers and fruits.
While pruning runs the risk of promoting yet more strong growth ultimately pyracantha greatly benefits from spur pruning which is why you sometimes see them trained elaborately.
So in summary it will begin fruiting when it's good and ready but you can help things along by applying potash soon and begin a pruning plan beginning in the winter