Cretaiole is not for everyone. They have certain restrictions they explain on their website. They also don't publicize prices. Which means you have to contact them first and wait for a quote. Their prices are not for every budget. Their method of conducting business is not my favorite, but clearly it works for them.
The OP doesn't mention budget. Knowing what someone is willing to spend per night goes a long way towards eliciting more appropriate recommendations. Without knowing someone's budget, one can throw darts at a map of Tuscany. No one has time for guessing games.
Pools can be pretty to look at, especially when they're sparkling clean and the views are spectacular. However, unless you visit a hot spring location, like Bagno Vignoni, pools in Italy are almost never heated. The pool water can be freezing cold, even in June. So be prepared.