I've had several pairs of 901s of different vintage. If setup exactly to Bose specs the wall that the 8 drivers face needs to an empty space as well as the adjoining walls for at least the first reflection point. Yes the Bose equalizer is a sore spot. And massive power helps (that's what they like).
I have a pair of 901 Series VI right now in my second system which is in the garage playing backward. They sound really good (for what they are) considering my garage is all concrete and 1000 square feet. They are sitting on typical crappy steel shelving (Lowes, Home Dopey) about eight apart. Quite a bit of bass that way as proximity to the ceiling seems to create coupling.
Interesting that everyone, including audiophiles, just kinda shake their heads because they go far past what they were expecting. Of course being driven by a tubed ARC preamp and ARC SS amp doesn't hurt.
So, yes you can run them backward to good effect.
Regards,
barts