Wow that is a big hole for a big pool!
Arhh, that is terrible news about the extra work that needs to be done. 8k seem a little steep though? Could you get a second or third quote? I guess you want the job sorted asap though.
I have seen the white exposed ag and I think it looks amazing. In fact I like it so much that I wished we had gone with the white instead of the grey. The white against that beautiful blue pool will contrast beautifully. And if exposed ag cracks you can notice it as much.