Phil, I have paddled these two boards and compared them ONLY in flat water.
We sell both Naish and PSH.
The PSH board most similar in stability to the Naish 9'6 is the PSH 9'6 wide Ripper.
As far as surfing them goes I have only heard good reports about both these boards.
It would boil down to personal preference as they are very similar.
The 9'6 WIDE AA is a different board with a more meat under foot, in front and behind.
It is more stable than the 9'6 wide Ripper.
The 9'10 Ripper is a board I have spent a bit of time on in the amazing waves we have been getting in the last week. At 90kg and 2 years under my belt, I am just starting to feel comfortable on it.
From my experience and feedback from customers, this is how I would rank the boards in terms of stability. Most stable down to less stable
PSH 10'6" wide AA 30" x 4 3/4"
PSH 10'6" AA 28 3/8" x 4 5/8"
PSH 9'6" wide AA 29 3/8" x 4 5/8"
NAISH 9'6" 29 1/4" X 4 3/8" PSH 9'6" wide RIP 29 5/8" x 4 1/4" (very similar to the above)
PSH 9'10" RIP 28 5/8" x 4 3/8"
I hope to spend some time comparing the 9'10 Ripper and the 9'6 wide Ripper, but my thoughts so far are that I prefer the line length of the 9'10 for getting into bigger, faster moving waves whilst the 9'6 wide Ripper is more 'hot-doggy' and will be easier to throw around in smaller waves.
Thats it from my perspective at least.

Andrew.A
PS: Don't you just love this time of year! Just drove down the beaches this am, and it is clean, off-shore with waves at every beach!!