After acknowledging that the Spotify community was big mad about the loss of the Spotify widget on Android, the music service committed to bringing the software accessory back in a future update. That update dropped within the past couple of days and should now be widely available to all.
As an added bonus, Spotify not only returned their widget, they managed to improve upon it as well. The new widget can be resized and it should be less buggy with improved stability.
Google Play Link