Awesome, post some more pics so we can all get 'coop envy' as your going along!
My only draw back with the floor was we had rats get in a chew the laminate to hell! That was just our bad experience however. Plus yours is off the floor, which is great.
Size wise - 4sqft per bird of coop space [min] for standard size chickens ie not bantams. So for 9 chickens you'd need 4*9= 36sqft or in other words a coop measuring 6ft*6ft. So your 6*8 sounds fine. Room for more!!
More space is required in the run than in the coop, probably 8sqft per bird, again for standard chickens.
https://www.poultrypages.com/best-large-chicken-coop-for-10-chickens/
What breeds do you have as some wont tolerate confinement? My icelandics for example are free range free spirits and cant wait to get out the run in the morning!
Ohhh, one more thing about 8-12 inches of roost space per bird. More if you have Large breeds like Orpingtons or Austra's. Been a while since hubby built ours, all this coop talk, maybe we are due an upgrade....