I have a T9 and use it in HA via the HomeKit integration. I wouldn’t recommend it if you don’t want to use it without the cloud as there isn’t an option to easily disable cloud support. (I was able to disable cloud access by blocking the sites it contacts). The main reason I disabled cloud access was because there isn’t a way to disable automatic firmware updates. Also I didn’t like it tracking the heating/cooling hours.
Another drawback for me is that manually controlling the fan isn’t supported via HA. I got around this by installing a Shelly relay on the furnace/AC electronics.