First, you will crack the frame with the spacers switched. They are too small (and hence put too much force onto a small area on an already weak frame), you can buy/make good spacers if that's really the route you want to go.
Second, you will probably have crazy vibes. 9" of lift is WAY to much for a slip yoke, not to mention how much stress is put onto the t-case output and u-joints.
You can point the pinion up some, but if you point it up too much you will starve the pinion bearings of oil and your diff will be burnt in short order. I would say 6-8 deg is the max for a truck that sees street time.