Did you manage to export *all* the fields from FFIX or did you just test out a few and notice they were too small to use?
There is a photoshop plugin called Alien Skin Blow up that can resize images with minimum quality loss, its hundreds of times better than photoshops normal method, you could give that a try, theres a free 30 day trial on their website.
I'm also interested in getting all the FF9 (and FF8 too) backgrounds, but there doesn't appear to be any way to batch export them, and considering each game holds hundreds and hundreds of backgrounds doing them all 1 by one would be extremely time consuming. If you're figured out how to batch them please do share, I'm sure a lot more people than just me will be interested.