I have been in a few earthquakes in Alaska, California, and Japan, but none stronger than 6.5. A level 9 is almost inconceivable. The earthquake scale is logarithmic, i.e. a 7 is ten times as bad as a 6. Because this quake was in an ocean trench and affected approximately 1000 kilometers of the fault line, the shock wave generated a rolling wall of water at least 40 feet high that sped across the Indian Ocean and impacted countries all along the shore line. The effects stretched all the way to Somalia from Indonesia, with islands disappearing beneath the flood.
Approximately 22,000+ people are presumed dead, but that number is far from accurate as many areas have lost all their modern communications beneath the wave. Until islands and shore communities can be inspected, it is a guess.
Aftershocks will continue for days and there is no way of knowing how many were lost in ships and boats swallowed by the flood.
[Updated 12:14AM 12/27]
[Second update of death toll 1:08PM 12/27]