The lack of Forte in Rockman 9 certainly ticked quite a few people off. Where was he? How could a character of his caliber be completely absent? Anybody care to explain?

According to developer commentary in the Arrange Album booklet, Forte was apparently undergoing "adjustments" during the events of RM9. Not only does this explain why he's absent but also as to why he appears on Dr. Wily's monitor in the final moments of the game. So, presumably, Wily was working on Forte. Why? Who knows, it's up for speculation.

Many thanks to Vixy and marshmellowman for the find!