Does everything obey God?

Yes, everything obeys him. No, Iblis disobeyed Allah.
Unto Him belongeth whosoever is in the heavens and the earth. All are obedient unto Him.
We said unto the angels: Prostrate yourselves before Adam, they fell prostrate, all save Iblis. He demurred through pride, and so became a disbeliever.
30:26 means that everything is under his control. Humans are given the free well to choose whether they want to be obedient or not and that is how everyone is tested. Still those who are disobedient are under God's control.