Of course, the AI has to be told to RESEARCH troops, and then told to BUILD them in order to use them!
I've heard reports of the AI using them before but it would never build very many even if it had the techs. I'm trying to get the Jraenar and the Terrans to use them more often in my own stuff. Some Some of the public modders could work on this, as well. Given that they now have a good effect on planet happiness, they ought to be included in every AI's design to some extent. It might be possible to make the "bloodthirsty" happiness type workable for the AI by using troops. Right now, all of the AIs use "peaceful" because they can't maintain happiness with the others.