I have bought the 9797 NXT base educational set. It didn't include any software.
Yes, you can - I have done so on numerous occasions, and actually prefer to use the retail software over the education version even when working with the education kit.
The NXT bricks in the two sets are exactly identical. You might need to update the NXT's firmware before using the brick with the retail software, however.
Yes, I do this with mine because the consumer version of the software has more features than the education (but no datalog and you won't have the pieces for the building instructions that come in the software in your kit)