The third update to Parking is live on the App Store today.
Parking 1.3 adds iOS 9 support and native handling of shared spot links. You can share your spot with anyone by sending them a link to your spot at thatparkingapp.com (here’s an example). Now, in iOS 9, that link will open Parking itself, and let you choose to save that spot locally—enabling notifications and showing your spot in your Today listing, or on your Apple Watch. Here’s a gif showing that flow (2.7 MB).