Depending on the speaker, that can be okay.
Depends on the amp and for that matter the speakers. Likely you would need to split each signal to separate amps that could then feed each speaker. So for example with my pre-amp, I can get a splitter cable from the pre for each channel and feed each to a separate channel of an amp. You would need a total of 9 amp channels to do it this way. With separates, it wouldn't be difficult. If you have an integrated receiver, I don't know if wiring in parallel or is series will work for you.
Depending on the speaker, that can be okay.
Depends on the amp and for that matter the speakers. Likely you would need to split each signal to separate amps that could then feed each speaker. So for example with my pre-amp, I can get a splitter cable from the pre for each channel and feed each to a separate channel of an amp. You would need a total of 9 amp channels to do it this way. With separates, it wouldn't be difficult. If you have an integrated receiver, I don't know if wiring in parallel or is series will work for you.