Since a few months i own a homey controller as well.It took me a while to find a solution to intergrate toon, so i would like to share some usefull links here.
An homey app is in development by Stefan Postma all credits to him and his contributors: github.com/StefanPostma/nl.vinceste.open-toon
This app must be installed via CLI method: community.athom.com/t/how-to-cli-install-method/198