Earlier discussions on this brought out that the civil suit can be brought regardless of what the DA and the GJ do or don't do.
The homeowner's lawyer would have to bring up the civil immunity statute early on, and the judge would have to make a separate determination as to whether the homeowner's force was justified under Chapter 9. If the judge determines it was, then he must dismiss the lawsuit.
That said, I do not know of any case in Texas where a person actually defending himself or another was sued, even unsuccessfully. I have read the occasional threat to sue in a newspaper article, but none of them seemed to even file.