Recoil?
Welcome to the forum and welcome to firearms.
Front sight, finger position, etc. All good advice so I won't repeat it. I will just start with my additions.
First of all, you are doing well. The SR9 was not intended to be a target pistol. If you can afford to purchase a second gun right now, get a Ruger Mark III target pistol (or Mark II) and switch off between the two guns. You will have more fun and 22 ammunition is a lot cheaper.
Get larger targets. Don't bother trying to put the rounds in the bullseye. Just aim at one point all the time. If you have a tight little bunch of holes (a "group") you are doing well. If it is 16" off to the left, don't worry. You are doing your part on the hold and the trigger. As long as you group is tight. To move the group over to where you want it, may require adjusting the sights, practising your sight picture or other ergonometric adjustments (you may be unconsciously holding the picture wrong or using the wrong eye, or even holding the gun so that you shoot left). The important part is that you are consistent. A shooting coach (professional instructor or just a friend who can watch your technique, or you could review your own shooting via the convenience of videotape) should be able to advise a different grip, stance or finger position on the trigger.
How does the recoil feel to you? After a few rounds of my friend's 500 S&W (or even moderate power .357 Magnums) I have to concentrate to avoid "anticipating" the recoil. (That is one reason to practice dry firing a lot). You can also diagnose if you are becoming recoil sensitive by loading a magazine with a dummy round (also known as "Snap Caps", available in most gun shops, or you could have one made up by anyone with reloading capabilities by simply putting a new bullet into a fired case with no gunpowder and a dead primer.)
Put the dummy round in the magazine followd by an unknown number of live rounds (have a friend do it or try to forget how many rounds there are). When you get to the dummy round it will be obvious if you are flinching or anticipating the recoil. If you test yourself at the beginning of a range session it will tell if you have ingrained the habit or not. If you test yourself at the end of a session it will tell if you are in the process of developing the habit. It is most telling if you run this test after you have been shooting for a while, because fatigue will make all your bad habits worse.
Which is your "master" eye? For a right-handed shooter, the right eye is "normal". There are plenty of left-eyed right handed shooters out there who do quite well, but the body's geometry is such that right-handed shooters should sight with their right eye and left-handers should sight with their left eye. That 7" to the left and 4" down mght be the result of switching eyes. Find out which eye is your master eye and then stick with it. If you can choose, choose the same side as your gun hand.
Always shoot with both eyes open. You can see threats with your peripheral vision better and closing one eye can affect the way the other eye sees, particularly if you tend to squint. If having both eyes open confuses your "sighting at the target" brain function (as you practice more, this will go away) put a piece of clear, frosted plastic on the lens of your shooting glasses (you do wear eye and ear protection, right?) that will make that eye unable to see the sights or target, but does not reduce the amount of light coming to the eye. This will force your master eye to really be the master eye.
Another possible explanation for shots low and left is that you may be tightening your fingers or jerking the trigger. See this diagnostic target
http://www.m1911.org/technic30.htm
or if the link does not work, paste this into your web browser:
m1911.org/technic30.htm
This target is for diagnosing right-handed shooters' problems. Left-handers should use its mirror image.
Breathing: You should not hold your breath. Rather, press the trigger while between breaths. Shoot during the time when your air flow is stopped, but don't close your airway. When you breathe, your rib cage is moving, making your shoulders and arms move. Shooting accurately from a moving platform is more difficult. Of course you would not do this in a defensive shooting situation, but the practice is good and will soon become an unconscious part of your trigger "kata", which can only improve all types of shooting. Some target shooters are even said to shoot between heartbeats because even your heart pumping causes slight movements in your body.
Good luck and good shooting,
Lost Sheep.