You don't happen to be a former (or current) SmartThings user, do you? If so, unlike the Hubitat skill, the ST skill on Alexa does support motion and contact sensors, so you could create a virtual sensor on Hubitat, tie it into ST with the community Other Hub integration, and then use that as part of an Alexa routine that could perform whatever action on the Alexa-only device. (You don't really need the hub online for this, just an ST location still set up in the ST IDE.)
So I guess the answer is still "no," but this is another workaround. 
One that interfaces directly with Hubitat would definitely be easier. In general, ZigBee and Z-Wave devices are better than Wi-Fi devices here.
