FWIW at 8 or 9 feet apart and sitting at a close near-field position (3 to 6 feet I presume) then I fear that you will indeed over-exaggerate some stereo effects to a degree that it becomes annoying on many recordings. Sounds will be to your left and right to such a degree that you may feel that you are sitting within the orchestra (a very unusual seat for a concert goer).
I'd suggest to try placing the speakers 4 feet apart (tweeter to tweeter) if you sit 6 feet back from the plane of the speakers. If you sit at 3 feet then place the speakers 2 feet apart.
I'd suggest to try placing the speakers 4 feet apart (tweeter to tweeter) if you sit 6 feet back from the plane of the speakers. If you sit at 3 feet then place the speakers 2 feet apart.