Hello and welcome to YT
!
I would absolutely *not* take a yorkie pup until at least 12wks of age - please trust me! They are so very fragile, tiny, vulnerable - and they younger they are, this increases exponentially! There are SO many developmental things and social learning things occurring btwn Momma and btwn littermates up to the age of 12 weeks -- that if you do take them before that age, your pup will miss out on that important learning as well.
An ethical yorkie breeder will keep puppies until 12wks of age, that's the standard for a reason. You can also confirm that via the Code of Conduct for at YTCA.org - where #8 says:
8) All puppies leaving the breeders possession will be a minimum of twelve (12) weeks of age to facilitate adequate socialization as well as appropriate emotional and temperament development through interaction with siblings, dam and other dogs.