Since you are only doing this for 9 months, I will recommend flying CX and crediting to AA. You get a lot more miles and get a status you can use in the US.

I switched over to the CX program, started from no status and got DM when I was gold and only flew 60k (instead of the required 120k) because it was all in F. But I'm using the CX program because they are more flexible with award tickets.

If I was in your position I would fly CX because it is more comfortable and credit AA.