I am using ws4py / CherryPy for websockets support, and would like to implement WAMP on top of it.
I thought of using autobahn but it only seems to support Twisted and asyncio out of the box.
Is possible to use autobahn functionality to extend ws4py, or is there an alternative way?
As you have already noted, Autobahn|Python supports running under either Twisted or asyncio. It includes a full-featured WebSocket implementation, and WAMP on top of that. So there is no need for ws4py, and we have no plans of porting the WAMP layer that Autobahn|Python includes to ws4py.
Twisted also supports running any WSGI compliant application. So in principle, you should be able to run CherryPy under Twisted. I have not tested that - I only tested (and regularily use) Flask on Twisted.