Questions about ITIN W-7 form applications

[HYDesmondLiu]

It requires original copies of passports applying for ITIN via W-7 forms.
It does not feel safe for me, because if passports are missing during the mailing, re-applying for a foreign passport in the US might be time-consuming and troublesome.

What if I go to the local Taxpayer Assistance Center (TAC) around me?

1. Can I get our passports the same day after application in person?
2. If so, do I get my ITIN number immediately? 
3. If I cannot get an ITIN number immediately, should I still need to file my tax return by mail to the Austin ITIN operation office?

[KrisD15]

If you use a Certifying Acceptance Agent or Taxpayer Assistance Center, they will look at your documents, make copies and certify them while you are there. They do not keep them at all so you would not be without your documents and you needn't worry that they would get lost in the mail.