Hi Roberto,
Yes you can, but need to take care of the process when you add an Unleashed AP to cloud while you have an operational Unleashed network in the same LAN. A factory defaulted Unleashed AP will still have a likely affinity (faster discovery) to an operational Unleashed master in the same network, than to join Ruckus Cloud. In order to avoid this, you may want to isolate the AP you want to add to the cloud away from existing Unleashed network first. I.e. the AP must have internet connection but cannot see the existing Unleashed Master. Once the AP points to Cloud and downloads the Cloud firmware, it can co-exist with an Unleashed network without issues. Note that Cloud firmware is quite different Unleashed firmware, so when you want to try cloud, you would need to create new configuration in the Cloud UI.
Cheers
Phal