Unlike UPS, I don't think Amazon can divert a USPS package. USPS will deliver on Monday. If you are not around you better make arrangements with the hotel because USPS will just drop it at the hotel and hotel will have to either refuse it and return to sender or forward it to you.

You really can't count on it being delivered on the guaranteed date 100% of the time. I've had occasional UPS and USPS Amazon packages delivered one day late due to routing errors or didn't make it on delivery vehicle due it package simply left at the last UPS/USPS facility prior to delivery.