In Texas, anyone can sue for anything. There is nothing in the law that prevents that. All PC §9.06 is saying is that, yep, nothing in the Penal Code abolishes or impairs "any remedy for the conduct that is available in a civil suit." So someone can sue over another's use of force or deadly force. This language pre-dates, by a long way, the CHL laws. It was first added by the 63rd Legislature in 1973, and slightly amended by the 73rd Legislature in 1993.
Section 83.001 was added to the Civil Practice and Remedies Code by the 74th Legislature, the same year, 1995, that the CHL laws first were passed. But the wording was substantially changed by the 80th Legislature in 2007, when the so-called "Castle Doctrine" was passed as SB 378. Here's a link to view the final text of the enrolled bill where you also can see the significant changes made to CPRC §83.001. Below is how that section read from 1995 through 2007, and the current version is below it:
CPRC §83.001 Prior to 2007 wrote:CPRC §83.001. AFFIRMATIVE DEFENSE. It is an affirmative defense to a civil action for damages for personal injury or death that the defendant, at the time the cause of action arose, was justified in using deadly force under Section 9.32, Penal Code, against a person who at the time of the use of force was committing an offense of unlawful entry in the habitation of the defendant.
The new version is much cleaner and, logically, encompasses the justified use of force as described in the Penal Code, period, not limited to an occurrence of unlawful entry into a habitation. (Thanks, Charles!)CPRC §83.001 After 2007 wrote:CPRC §83.001. CIVIL IMMUNITY. A defendant who uses force or deadly force that is justified under Chapter 9, Penal Code, is immune from civil liability for personal injury or death that results from the defendant's use of force or deadly force, as applicable.
So, in essence--again, only my opinion--nothing in the law prevents someone from filing a civil lawsuit as a result of your use of force. However, if your use of force is justified under PC Chapter 9, you are immune from civil liability for personal injury or death.
The net message, to me, is that if an incident is a "good shoot," it is extremely unlikely you would ever see a civil suit. Only a bad guy, or bad guy's family, who has so much money that they would be willing to simply throw it away just to cause you some temporary grief would ever file a suit. Your civil immunity under CPRC §83.001 means that they can't win damages from you. Only their attorney would make any money out of the case. What's more, you would be free to counter-sue for your costs to defend the suit--and possibly for other damages--and would be likely to win that one.
Time will tell, but I expect civil lawsuits following a justified use of force to be very rare birds...