It can take a while, personally, and I don't own dogs, but if I did I wouldn't worry until they were about 18 months of age and both hadn't appeared.
I'd missed that bit of the question, but yes, as cryptorchidism is considered something that may be genetic, bitch owners wouldn't be interested if they are aware, and obviously you wouldn't want to risk this passing on to pups.Lots of good advice. As a bitch owner I’d probably not consider breeding with a dog with an undescended testicle. In my country it wouldn’t be permitted anyway. Not to say you couldn’t but unless he was exceptional in the show ring (which is unlikely as he’s currently only got one) I can’t imagine bitch owners flocking to your door. The ones that might probably wouldn’t be the ones you’d want. Give it time, hopefully it’ll all come right.