Yes, I have the LaserLyte in 9mm and looking at the link you posted on Amazon it's available cheaper there than from the company itself. I highly recommend one for dry-fire practice. What I've done is purchase 1/3rd and 1/6th size IDPA targets from BenStoeger, then I affix them to the walls of my home office at known distances. I also use a one inch diameter orange dot which I "fire" at. I practice drawing from my holster and firing. The laser will tell you exactly where you're hitting. Keep in mind you have to rack the slide each time on a striker fired pistol to get the laser to "fire." For DA every trigger pull will result in the laser "firing." If you buy the LaserLyte be sure to purchase extra batteries - it takes 3 small circular batteries. Also be sure to unscrew the LaserLyte after each use to prevent the device from accidentally activating and prematurely wearing out your batteries. It's a good product and I enjoy practicing with it several times a week. It's still not as good as going to the range and live firing but in the cold winter months it's a worthwhile use of your time.
You are correct, in live fire you call your shot off of the front sight and you won't get the noise and recoil using a LaserLyte device. All the laser will do is tell you where you'd have hit the target with one shot if you'd have had a round in the chamber. It's a good device for dry practice when you can't get to the range and want to practice trigger presses at simulated distances indoors at home using miniaturized targets. I also like the "Dead Trigger Drill" created by Rob Vogel where you place your FS on a target and keep pressing the trigger such that your front sight experiences minimal movement during those trigger presses. Another good drill is what I call the Hawkins 812 Drill, created by Harold Hawkins, where you practice your grip by squeezing either a blue gun, a lower or an unloaded pistol as hard as you can 8 times a day, for one minute at a time, with only 2 minutes rest in-between. That drill does amazing things for your grip. Hawkins calls his drill something humorous but unmentionable but trust me, it's a good drill and makes more sense than buying those silly grip strengtheners you see advertised in the gun magazines. I like to do the 812 drill using a blue gun with an orange front sight pinned to a ⅓ or 1/6 sized IDPA target from 10-25 feet away. I find it helps my accuracy on the range quite a bit because I used to have a weak grip.