(i.e. you don't want to create and login with a volumio.com account).
Navigate to http://volumio.local/dev
or http://yourvolumioip/dev
, where 'yourvolumioip' is the actual IP address of your device eg. 192.168.33.45.
Find the SSH section, and click 'enable'. From now on your SSH will be permanently enabled.
SSH into volumio box. Username volumio, password volumio. ssh [email protected]