P9 is "approved" firmware. S9 is still under development. Wait till it is posted onto BenQ's Global site. Personally, I finally got S9 to work (got a bad results twice, but flashed it a 3rd time and it works). Now that S9 is working reasonably, it makes worse scans, but with marginally better odds at data integrity. Go figure. Anyway, if you're already working well on "P" just wait until "S" is finished.
I went to the docter and said: "Doctor, it hurts awfully when I move my arm this way." puts elbow into ear The doctor said: "So, don't move your arm that way."
Seriously, though, my theory is a bad flash because I've seen that four times firsthand. Try flashing from windows safe mode or with the .cvt flasher using the dos flash method if possible.