What paperwork do you feel you need?
I certainly wouldn't rely on the pharmacies to know what's needed for various travel. When I got the test done at Costco before my last trip they gave a print out that had my name and information, the date of the test, the negative result, that it was an anitgen test, and the pharmacist signed. Since no one even actually looked at it, I'm not sure if it would have been an issue. For cruising I would want to make sure it's printed and not handwritten, but otherwise I don't think there would be an issue. Costco indicates it's a "asymptomatic covid antigen test" and does not mention travel anywhere. I don't think any of the sites do.
Costco - $16.99 - you can book up to 22 days in advance depending on the location - -
https://costcopharmacy.ca/appointment
Walmart - $19.99 - you can book up to 25 days in advance depending on the location -
https://portal.healthmyself.net/walmarton/forms/Dpd#/
Rexall - $30 - some locations only have 3 days in advance, others go up to end of December -
https://www.rexall.ca/covid-19/test...t91s6weTE8tSVmHc_p8o35fLGnzne7M0Bf6tjFbpHhQkQ
Shoppers Drug Mart - $40 - you CAN NOT book online at the moment and every place that does testing confirmed you can only book 6 days in advance (walking in to book or calling)
https://covid-19.shoppersdrugmart.ca/en/testing/antigen-screening