I am going to travel next Sunday 26, is it possible to perform and obtain the COVID PCR at the airport that same day?

If you can but I do not recommend it as a doctor, the test is 24 hr before you request the US

I travel to P.R on Monday and if you have all the vaccines you just have to show the proof that you have them.

Testing takes 24 hours when it is for travel

It has to be 24 hours before.

The PCR test does not come out the same day, it takes 2 to 3 days