Socializing with other vaccinated puppies

Hi. We're bringing home our puppy on Tuesday. He will be 9 weeks old with his first set of vaccinations. My brother-in-law and his wife also purchased a puppy this last week, I believe she is either 8 or 9 weeks (a Greater Swiss Mountain dog, if it matters). I'm not sure if she has had her first set of vaccinations but she was purchased from a reputable breeder so I'd $#@!ume yes. Anyway, is it safe to let the puppies play together without their full sets of vaccinations, since they're approximately the same age?



Edit: sorry, the title should read UNvaccinated

Socializing with other vaccinated puppies