You want a stud that is 7 months old or older if you plan to AKC register the puppies.
Here is the regulation from AKC
Chapter 3, Section 5 of the Rules Applying to Registration and Discipline reads as follows:
"No dog or litter out of a dam under eight (8) months or over twelve (12) years of age at the time of mating, or by a sire under seven (7) months or over twelve (12) years of age at the time of mating, will be registered unless the application for registration shall be accompanied by an affidavit or evidence which shall prove the fact to the satisfaction of The American Kennel Club."
The affidavit or evidence would be the vet checking a sperm sample from the male at the time of breeding and certifying the dog as fertile - they have rules on who can do this too.
Most people prefer to use a dog old enough to have been health tested and proven clear of hereditary issues such as eye or hip problems etc and that usually takes until the dog is 2 years old before that is completed.
If you see a puppy you like consider breeding to that puppy's sire as the sire is 1/2 of what you see in that puppy!
Personally I'd not offer or use a stud puppy that young as I prefer both parents be cleared of possible health issues before breeding.
This site talks about health clearances in this breed
You may find these sites interesting too
Hope this helps you!