So are ipad owners who want to listen to iTunes stuff buggered when it comes to high quality audio wirelessly?
Any issue with the S9 is unlikely to have anything to do specifically with iPad. If you don't like the S9 sound quality, choose any other Bluetooth stereo (A2DP) headset.
The only issue I have with the S9 is wearing comfort. The latest version is a bit more comfortable (be careful - a lot of sellers selling an old version...) but the behind-the-head design means you cannot lay down on your back and listen.
I had a nice Sony A2DP headset with an "earcup" design. (Unfortunately, I lost it...) Problem with it is that it's an "elongated cup" design and really not big enough for anything bigger than a child's ear...
I don't have any issue with sound quality of either headset. But that's a personal judgment. You have to decide for yourself as with any headset.
A2DP is always going to be a compromise vs. a wired headset. A2DP uses lossy compression (ironically, the mono Headset Profile doesn't compress...) and, at least today, it is almost certainly being re-compressed.
A2DP supports the SBC codec and, optionally, several others including MPEG 1/2/4 AAC, ATRAC. Theoretically, you can avoid re-compression IF the headset supports the same encoding as your source material, AND the chipset and driver in the computer/notebook/iPad/whatever are able to "pass through" the digital stream in encoded form. That's in theory, but unlikely that anybody has implemented this.