UPS drivers work to deliver packages between the hours of 9:00 AM to 7:00 PM which is their normal working hours.
However if the UPS driver has a lot of packages to deliver the UPS will sometimes deliver until 8:00 PM and even later depending on how backed up they are with packages.
The UPS driver will stay out until they can deliver all the packages on their truck so if your packages is out for delivery then it will be delivered that day even as late as 8:00 PM or later.