No 9th row seats are available, so I chose row 18, which also an exit row (row 10 is also still available. should I choose it instead ?).
First of all, only 10A and 10F are true exit row seats (more space), no matter what AA's silly seat map says. 10B/C/D/E are quite ordinary seats.
10A and 10F have no underseat storage, and not even a seatback replacement (the bulkhead is a full row in front of you). On a lightly loaded plane, you might be able to store under 10B or 10E if no one is sitting there, but on a Y1 flight on 12/23 that's not to be expected. So if you can use underseat/seatback storage, row 18 can be better than 10A/10F. 10A/10F's only advantage (on a full plane) is endless room for your legs (plus earlier to exit plane), but it has storage disadvantages.