Can sitters charge more for additional hours past 24-hours?

Here's a scenario: A dog is dropped off at noon on a Saturday and isn't picked up until the following Sunday at 9pm. If my math is correct, the dog was with the sitter for 8 days and 9 hours. Rover seems to not charge for the 9 additional hours. How have others handled this? Can a sitter charge a rate for every hour that's past the day marker?