I had to update my pioneer speaker firmware and it works fine. As I said, Connect is still rolling out to android users but when you have it, the connect icon will show at the bottom of the album cover view
Yes it show greyed out in cover view and not at all in the play bar. Once you power on a hardware device, (waits for his speaker to boot up) the display is the same but clicking on the grey speaker icon from cover view enables you to select your speakers after which yu see a green speaker in cover view and in the play bar at the bottom in other views.
I'm not sure about that. There was some talk elsewhere that the icon didn't show until the app detected compatible speakers in another thread. If you updated the firmware for your speaker with the connect update and you have connect on your android, you should be able to connect as follows:
Make sure the speaker is powered on and on the same wifi network as your mobile.
Open spotify on mobile and go to album cover view.
Tap on the connect icon at the bottom which takes you to the connect page showing compatible devices.
If you don't see a connect icon in step 3, connect hasn't been rolled out to you yet.
It is a phased rollout to premium subscribers and is independent of version. If you don't have it yet, you shouldn't have too long to wait. The original announcement said "Spotify Connect will roll out to Spotify Premium subscribers on iPhone, iPad and home audio systems over the coming months, with Android and desktop updates to follow."