In my opinion, 9 days for Asia is a little insane, sorry (but very true). The problem being that Americans are very fast paced, and most of the locations in SE Asia are laid back and very slow going. If you want a real experience, then I suggest my favorite of all - Hanoi. Certainly not the prettiest, but I feel it's the most exotic, very affordable, and the Vietnamese are very outgoing - and they love Yanks!
Korean from ATL is a very good choice. My last trip in Dec '12 was on both Korean and Asiana through Seoul (this airport is one of the 3 best in the world). Seriously, you need at least to double that 9 days.
Go with the prearranged VOA visa for Vietnam (buy from any agency in VN, but I use visa4vietnam.com). Your airline will not let you board for VN without a visa or VOA letter. In Hanoi, I like the
Art Hotel on Hang Dieu ($35. to $65.) - these people really treat their guests like kings! Have the hotel meet your flight - Hanoi taxis are a pain in the rear.