In the same dominant chord a sustained 9 and a natural 9?

[jsaras]

It's just a melodic leading tone.

Like a passing note?? It's on the weak beat right??

Leading tones do not have to be on the weak beats, nor do they have to resolve immediately or resolve at all. The musical context and intent dictate how far you can stretch things. If it's a Chopinesque waltz, the leading tone will probably resolve immediately. If it's a Wayne Shorter solo, the entire phrase may never resolve.