Conversely.
I went down to my local rubbish tip at 8:50am to join a queue for opening at 9am. Covid 19 restrictions on the number of car allowed in at one time meant that I had to wait until 9:15. I had a car load and because I wasn't parked close to the skip it took around 15 minutes to empty the car. When I left there were free parking spaces in the tip and no waiting queue. It doesn't always pay to turn up early!
Its a bit like going to the supermarket with an opening time of 8am. Between 8am and 9:30am you are likely to run into a lot of the school run parents with their brats in tow who shop before or after dropping off their kids at the school gate. Much better to leave it to 9:30am.
These days when using Royal mail I pay for the postage on line and print out my own label with the QR code. With a jiffy bag size item it's then just a matter of finding the nearest post box, which in my case a 60 walk away from my house.