I've definitely attacked a city, fought a battle with some heroes and troops (maybe 4-5 total), not captured the city, attacked again and fought the barely-revived heroes together with the non-previously-involved troops and city garrison. It could be that there were more than 9 units in the city, I didn't check. It was still confusing, though.

sometimes I have captured a city, but some of my army's troops are left outside the city and then are attacked and killed the same turn

if it's on the same turn, wouldn't this be like creating a diversion and attacking the city from different sides or a pincer attack?  maybe this is a way to take well-defended cities?  do we need a way to choose among defenders?

mmmmmmmmmbump!