Something tells me that you're going to have too many chickens in your backyard.
Overpopulation of any creature over a limited area will cause a decline in health of those creatures.
For nine hens I would be sure to have a coop a minimum of 36 sq ft. A 4x8 coop gets you pretty close, but will be tight. For the run I would go by the 10 square foot per chicken recommendation. For nine chickens it would be 90 square feet. Your 10x10 run that you propose would work. I would build it as a fixed coop and run, not to be moved around...more is *always* better. I would let the chickens out to free range for an hour or so late in the evening, just to help them keep their sanity.
But, having nine chickens in a 100 square foot run will result in a barren moonscape. The ground will become packed down and saturated with manure. Then the rainy spell comes and it begins to have an incredible stink to it. Having a 60x30 backyard tells me you probably have a neighbor across the fence from you. They'll probably smell it, too. Oh, and flies...there will be flies. Just saying...
Ok, so what do you do? Deep litter. Build your run/tractor tall enough so that you can raise the ground-level up by a foot. Pile in the wood chips, dried leaves, dried grass clippings, twigs, cornhusks, etc.,...anything to get a
thick layer of carbonaceous "brown" material down on the ground to balance out the nitrogen-rich chicken manure. This hopefully will create a healthy deep litter system that will host organisms that will in turn devour the droppings while at the same time imparting some health benefits to the litter. And, it will help with the smell and the flies.
The other thing to do is to start feeding them fermented feed. It is noted that one benefit of feeding fermented feed is that the chickens' poop doesn't smell nearly as bad...some people report that feeding fermented feed causes the poop to not smell at all! Besides helping with the smell it can cut your feed bill almost in half in some instances. The chickens also get more nutrition from fermented feed...lots of probiotics, too. Win, win, win...
Oh, and as for your grass surviving nine hens....I think if you do some research you will find that what the other posters have said about the chickens stripping it bare is correct.
I'm not trying to be a pessimist with the above information, just wanting you to be aware of what you're looking at. A question that I have is "Do you really need nine hens?". That 100 square foot run and 32 square foot coop will work a lot better with four chickens.
Best wishes,
Ed