Welcome Kevin! If ribs are taking 7-9 hours to be fall-off-the-bone done, and your temp is correct in the smoker, it could simply be your ribs. Depending on the size and source of the ribs, they'll take more or less time. I usually do 3 racks of baby backs from Sam's in under 6 hours, and they pull clean from the bone. Odd yours take that long, but if it works for you, that's great!