I chose the 9-18 over the 7-14 ...

Yes, and the 7-14 can cover 7-9 without changing lenses.

In practice, I rarely find a need to quickly change between UWA territory (7-12) and ordinary WA territory (14-18). I rarely bother to mount the 7-14 unless I have a clear idea for an UWA shot in mind and I am very unlikely to use it at any FL longer than 12 mm.

Above that point, I am happy with the 14-45 which allows me to move between 14 and 45 without changing lenses.