Well, there's a lot of logic. Dogs can either produce, or they can't, so you may as well breed them and see.

I haven't bred any 9 month olds, but I have no problem breeding a bitch past a year of age.

We bred the 11 month old Lu Lu to the untouched Hornet, and at 13 months she produced the highest-percentage Poncho stud to ever, Ch Mr. Serious, POR, ROM

Jack