In that 1999 article, he is actually acknowledging that the plan was originally for 9!

The long-standing perception has been that the complete Star Wars saga is a 9 film cycle, and after Episodes I through III were finished Lucas would move on to Episodes VII, VIII, and IX, resuming where Return of the Jedi had left off. "That's really not part of the plan AT THIS POINT, " he says. "When you see it six parts, you'll understand. It really ends at part six."

What was all that about how I'm not facing up to facts when they are presented?