You can play from a Sonicorbiter OS based device to a Chromecast Audio or otehr Chromecast enabled device.
To do this you need to install the BubbleUPnP Server and MinimServer (DLNA server). Both of these can be installed from the Software manager
sonicorbiter.com -> manage -> Apps -> Software Manager -> Avalible Apps
MinimServer will make all your music available to any DLNA capable device
BubbleUPnP Server will make any DLNA server available to Chromecast.