This is a most important point. The contractor left you with a partially completed pool. However, if he has not paid his subcontractors they could come back to you (and other homeowners who have non-completed pools as well). So having a lawyer will help sort through all the possible scenarios that may become reality.
This is unfortunately a real, and sucky, possibility. In California, contractors are supposed to issue you a prelim (preliminary lien notice),
before they begin work. These prelim's serve as notifications of who everyone is that is going to work on your project, and that they have the right to lien your property if they don't get paid. Then it's up to the customer (you) to demand lien releases from the subs
before paying the general. Something of which most consumers are unaware, unfortunately.
Technically, if a sub never issued a prelim, then he can't later lien you. But even in CA, that's a grey area, because they can (and will) lien you either way, and then you have to defend against any that failed to issue the pre-lim. Which can be an expensive proposition, even if it's later determined that they can't collect. Then it's up to the judge to decide who gets the bill. If a sub did the work without getting paid, you technically did receive the value of the work. That's the sticky part. Basically the judge has to decide which of the innocent parties, you or the sub, is going to get screwed. I have no idea how that works in TX.
Did you ever receive any prelim's? That would be something to discuss with your attorney. The ideal scenario is to have the aforementioned doc in hand, the one that cancels the contract, awards you all the materials on site, and serves as a lien release for every sub-contractor that worked on the job. That's a wish list that may be difficult or impossible to attain, but that's the goal. In fact, if you'll be interviewing attorneys to find the right fit, a good indicator of that fit would be an attorney that rattles off that list to you, before you mention any of it.