p500 vs p9100

I am starting a graduate program which will require taking photos of structures, monuments, buildings, etc and will require a high level of detail. I currently have a canon point and shoot (which I still LOVE for everyday use) that doesn't have enough zoom to capture detail from a distance - only 3x optical zoom. I'm looking for something with at least 12x optical zoom and I'm mostly considering the older models (p500 instead of 510 and 9100 instead of 9300) mostly due to my limited student budget!

Anyone have any suggestions on which is the better camera for me? While I need a lot of zoom, I'm not sure I need as much as the p500 offers. Which is likely to capture a higher level of detail and better image quality to meet my needs? I'm open to other cameras outside of Nikon, in fact, I love Canon but can't seem to find one that I love within my price range.

Thanks!