I have heard of a lot of guys going International from 9E. There are a lot of CAs who are fed up and are here for a lot longer than they every anticipated . . .
As far as being understaffed, they like it that way. Until we are cancelling 5% of flights due to crew availability (or lack there-of), we wont see more pilots LOL - thats probably an overstatement but you get the point.
ATL is very Senior for lineholders then very junior on reserve. The latter part of that statement is especially true for FOs. There isn't much movement out of ATL since the seat lock is still in place and no upgrades for FOs to escape.
Good Luck!