No such feature exist with Nest Wifi.
For kicking of devices that know your Wi-Fi password, the only option with Nest Wifi is to change the Wi-Fi password.
For removing stale, disconnected devices from the devices list in the Google Home app, the only option is to wait until they are automatically removed. I think this time is 30 days. If you want these devices removed sooner, the only known workaround is to factory reset all Nest Wifi units and set them up from scratch. More info:
We haven't heard from you in a while so we’ll be locking this thread if there’s no update within 24 hours. If you're still experiencing problems, please feel free to start a new thread and we'll be happy to help.
Thanks for the help here, olavrb and Mel.