A:Answer HomeKit support is not built-in to the Sony XBR65A9G TV. However, many features of HomeKit may be added by connecting an Apple TV 4K box to one of the TV's HDMI ports.
The Apple TV 4K works extremely well with this TV. Apple TV supports both Dolby ATMOS and Dolby Vision. If HDMI 2.1 cables are used between Apple TV box and the Sony, the full display capabilities of the TV are available in the picture and sound delivered by the Apple TV box. Also, both the Sony remote control and the Apple TV remote can be used to control the Apple TV app selection, to invoke Siri controls, etc. I find picture quality for source media streamed through the Apple TV box to be better than that same media streamed directly into Sony TV apps. The Apple TV box does an excellent job of up converting non-Dolby Vision media into Dolby Vision format.
Finally, the Apple TV box can run the HomeKit app in the background, and execute timed HomeKit actions to your various HomeKit lights and devices.