I would say that the bitizen with the dream job is more valuable than a highly skilled bitizen.
For example, a highly skilled bitizen would complete the job of ordering 100 items in, lets say, 10 minutes instead of 15, which isn't a bad deal.
BUT if another bitizen (even if they have low skills) dreamed of working in that level they would order double the amount of items in 15 minutes, creating 200. This equals more credits and more time between the next order. Plus, whenever you reward a bitizen with their dream job you get handed an imperial bux that you can save towards a better elevator (I've already bought the 75 bux one).
- Level 9 bitizen = Less ordering time, normal amount of items
- Dream job bitizen = Normal ordering time, more amount of items, free imperial bux
You may also be lucky enough to come across a level 9 bitizen with a dream job.
Happy gaming! :)