The book it now price does not calculate overages when the stay is beyond 24 hour increments.
Your profile shows a Nightly Rate of $20 but Night for Stays of 1 day or More for Only $15.
Basically, it calculated your nightly rate at $30, based on Night for Stays of 1 day or More $15 x 2. After Rover takes standard 15%, Rover will pay you $25.50. The math is correct, but you may want to review your pricing and you may want to use the extend a stay feature if this goes much beyond 2 nights.
Rover is set up so the nightly rate is based on 24 hours. In this case, a 9AM start should end at 9 AM 2 days (48 hours) later. You know it will end no sooner than 11 AM (on the 31st) 2 days later, and you may not have charged more for 2 hours. However, if it goes until evening, you could have informed the pet-parent that would result in a daycare fee for additional hours. I'd suggest things go more smoothly if this is discussed during the meet &greet before booking it, so you can add compensation for additional hours as needed.