We have tried IA-7 with our S-9 speaker (which has 86dB @ 1 W/1M) and with moderate volume it is great. We won't recommend IA-7 for S-9 because it will not have sufficient power to bring up the best in S-9.
I think given the size of the room and moderate volume level listening, IA-7 will be fine. The 22,000uF cap will be sufficient short term peak power need.
