I'm making some guesses here - what does your company do (Service? Manufacture? What?)
Umm, well - if an independent lab says they're QS certified, ask to see a copy of their certification. See what it says. Get a copy and FAX it to me. I'd love to see it!
QS9000 was targeted at companies who manufacture items for Ford, GM and/or Chrysler. Labs provide a service, not a 'product' per se. To my knowledge an independent lab is not 'certifiable' (a word here - companies actually register to ISO9000 [and qs9000 for that matter since a qs registration is an ISO9001 registration with additional stuff]. Yes - everyone says they are 'Certified' but they are [call me Clinton for the use of definitions] really REGISTERED. That's why they're called Registrars - they register companies. They don't certify a thing.)
There are places to contact and you can be audited to their 'spec'. The A2LA folks are at: https://www.a2la.org/ if you're a lab (what does your company do?).
NO - you do not have to be 'certified' to do your own calibrations, but you have to have a documented system and calibration procedures. You must also be ready to show evidence that your standards masters are traceable, etc. Standard cal stuff.
Maybe thaqt answers a few of your questions.