With Google Home you need to add a
Project to the developer console with the matter Vendor ID and Product ID you are using.
https://console.home.google.com/projects
For development you can use a Vendor ID of 0x8000-0x8006 which doesn’t require certification.
Most ecosystems will preset a warning that this is an uncertified device (a bit like side loading on android) only google requires some custom settings in their developer console.