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I'm not an expert by any means but the 9 degree down angle on a 28" long drive shaft sounds like a problem for the u-joints. I'm sure others that are more experienced in this area will be along shortly to provide insight and correct me as needed.

What WICruiser said. I put your numbers into Spicer's Driveline Angle Calculator LINK and came up with 16 degrees on the rear u-joint. WAY MORE than the 3 degrees recommended. Changing the pinion angle doesn't help much, so it looks like you'll either have to drastically angle the engine down at the back or lower the whole engine/trans assembly to change the driveshaft angle. I was reluctant to respond last night as I figured something was wrong with how I was using the calculator. But WICruiser's response reinforced what I was seeing.

One of us must be wrong in some way. I did the same inputs and it asked me if the drive shaft measurement was a direct measuerement off the shaft or the difference between pinion and shaft, it's the measurement off the shaft. As I see it the difference is only about 2 degrees. I hope I am correct but I have been wrong many times, just hope this is not another of my mistakes.

If you click on the "show diagrams" button, it shows the driveshaft angle off horizontal and that's where I put your 9 degrees down, and came up with the 16 degrees on the rear u-joint. I didn't see it asking if it was the difference between the pinion and shaft. Are you using the same calculator I linked to?
I have to admit that I've never set up a driveline before, but understand angles. I agree that we're thinking about it differently.
[on edit] I think I figured it out. I set all all the angles to up (which would be going from rear to front) and it comes up with the following. Looks like you're pretty good.