No support right now for Apple HomeKit and RA2 or HomeWorks.  I contacted Lutron about this last week and spoke with the product development team.  It's something they are evaluating, but not currently in the product road map.

I've already had clients asking for this with RA2 and HWQS and would like to see it supported.  It's difficult to tell a client their buddy who spent $350 at the apple store on Lutron Caseta can control his lights with Siri, but their $60k Lutron Homeworks system can't do the same.