Reason for skipping DB8 was that Aston Martin thought that people would believe the '8' signified that the car had a V8 engine, which it clearly wouldn't as the DB9 has a uprated V12 engine. Also, the new AMV8 which resurrected the V8 range of cars (last was the Virage) is due to come out in October - going to the launch tomorrow!
Hope that gives an answer to the question.
Hope that gives an answer to the question.