Yes, Revelation 1:8 is talking about the Almighty. We also know him by the name Jesus. That entire first chapter of Revelation identifies the Almighty as the Lord Jesus who rose again from the dead, and just a verse later of the title "Almighty" we see "Alpha and Omega" confirmed with "first and the last" and linked to "I am he that liveth, and was dead."
So you believe the Almighty God had been killed and rose again from the dead?
LA