an additional point of clarification...

"#9 of 21 on Upgrade List" indicates your position on the upgrade list at the time you checked in or last viewed the current upgrade list. It can change as additional pax check in online or at the airport. You can monitor the position on delta.com under "Itineraries and Check-in".

It looks like you do have a good shot at an upgrade at the gate, with 18 FC seats available.