I guess I just can't imagine Demyx with anyone other than Axel and/or Roxas. Huurrr...
Here's an interesting thought(that is, if you're an Earthbound fan).
You need to get eight melodies from eight sanctuaries. You need to pray nine times in order to defeat Giygas. In Mother(Earthbound Zero), I'm pretty sure there are eight pieces of the melody there and you need to sing nine times to defeat Giegue.
Heh. Axel is number 8 and Demyx is number 9 in the Organization. Seems that in Earthbound, eight and nine tend to be the most important numbers.
I guess it's just coincidence(especially since only Xemnas' and Roxas' numbers were the only ones that were certain before Kingdom Hearts COM was made), but it's a pretty neat idea.