I think they are still trying to figure out how the heck to make DQ9 work in America. One possibility is making it DSi exclusive and using that smidgeon of extra juice to power online games with voice chat.... something executed well in a now years old Pokemon game but an uncommon feature nonetheless. I think that at least here in America, the people looking to play DQ9 would upgrade a system for more comprehensive online functionality without many sales opportunities being lost. In other words, here it is only the "core" that are dying to play DQ9 while in Japan quite literally everyone and their grandparents are playing it. Of course, it could be possible on the DS lite but I am not intimately familiar with either piece of hardware.