Like Reason 10 and Reason Essentials 10, ReWire is 64-bit too. Note that 64-bit ReWire needs to be implemented in both the device application (Reason, Reason Essentials) and in your host. Please contact the manufacturer of your ReWire host to see if they support ReWire 64-bit.
Note that Reason 11 and later does NOT feature ReWire, since you can use Reason 11 as a Rack Plugin in a compatible host DAW.