Our first was 6 weeks early and had to be kept on O2 for a few days until the Docs were satisfied that his lungs were developed enough and had the strength to function on a stand alone basis.
As I understand it the respiratory system is one of the last systems to "mature" in the womb.
Kiddo comes a little early, they get concerned as far as development of the respiratory system.
9k is going to make it a little tougher on the kiddo but I would think if the Docs were really worried they would have him down here in an incubator.

