Well in my opinion Megaman & Bass qualifies as Megaman 9 - I don't know why they didn't call it that way in the first place (but there are lots of questions you mustn't ask about the Megaman series (especially the X one) anyway). It's as valid as X6 being the next title after X5 just as Half-Life 2 is to Half-Life 1 or Warcraft III is to Warcraft II...

Well I'll call it Megaman 9 now as they say but it imo is not correct just like for the numbers of the earlier Final Fantasy titles (at least in non-japanese countries)...

Enjoy your meal
Toast