As I said before, a quality gun should jam less than once every 10,000 rounds. There's a really great group of guys out there who do reliability testing. The M&P , Sig, & HK USP from their testing are some of the most reliable. In their testing they went 35,000 , 15,000 and 10,000 without jamming respectively. Carrying a second gun isn't a great idea because then you have to train to fire from that position too. You should also be training with snap caps in your primary firearm to train in case of jams. A quality shooter can clear a jam in 1 to 2 seconds.
You need to do serious research into calibers and be careful of ammo claims.
Frangible ammo has been around since the 50s, yet no law enforcement agency , military or other group uses the ammo. The only group that regularly uses it currently is the US air marshal service.
Frangible ammo is often touted by various companies as the 'best' ammo possible, however you need to understand how firearms kill or incapacitate.
People are killed either from CNS disruption (Brain) or lack of oxygen to the brain (blood loss). The second is the less reliable killer as it's nearly impossible to tell when someone is about ready to lose consciousness during a gun fight.
Now , frangible ammo states that it is the better ammo to incapacitate because it causes a larger temporary cavity. The problem with this is the fact that temporary cavities don't kill people, permanent ones do. The hope with frangible ammo is that it will sever more arteries & blood vessels due to rapid and extreme expansion/fragmentation. The problem with this idea is that all of the major organs which carry the most blood (and have the most arteries) are more than 6" from the surface of the skin. In the case of your 85gr 9mm ammo , it will penetrate no more than 5" in a human body. Furthermore, 12" of penetration is what the FBI demands every single caliber meet before they will consider it for usage. This is because they found out that many criminals were surviving shots due to the position of their bodies during bullet impact. In many cases criminals attempt to fire from concealment or cover, thus meaning the chance of a bullet impact from the side is extremely high. In these cases it takes no less than 12" of bullet penetration to make impact with any major internal organs.
Cover and concealment is also a major factor when picking the right ammo. Your frangible ammo will not penetrate intermediate barriers. So , should someone break into your house, you will be unable to fire through the drywall to kill them, but as long as he is armed and not using the exact same ammo as you , he will be able to shoot through a wall and kill you.
Example : Last year there was a CCW incident in Dallas Texas involving a permit holder , a police officer and 2 criminals. The CCW holder was a jeweler and called the cops because there was a car parked behind his store selling drugs. He pointed the car out to the cop and waited in the front of his store for an arrest. When the dealers saw the cop, they took off attempting to run him over. The cop fired 6 times at the driver of the car, through the windshield in an attempt to kill him. Incidentally a 40s&w is extremely poor against windshield glass (as is 9mm) without very specific bullet types being used (bonded). The driver was not effected although he had actually been shot 4-5 times, the bullets either made it no less than 1" into his body, or literally bounced off him due to loss of energy. The jeweler heard the firing and came out only to see the car with the guys inside and 6 bullet holes in the windshield. Assuming the cop was shot or killed, he fired his 1911 two times at the driver , again through the windshield. Both round struck him center mass and caused rapid incapacitation. The driver unable to control the car crashed it into a telephone poll and was found dead. The 45acp penetrated the windshield glass while the 40s&w did not.
Barriers should ALWAYS be a concern for a person carrying a firearm. Here's another major example : http://concealedcarryholsters.org/wp-content/files/FBI-Analysis-on-PA-Police-Shootout.pdf
This is the autopsy of a man who had a shootout with police officers in PA. He was shot in excess of 17 times, practically every single handgun round did not penetrate more than a inch or two. He was eventually handcuffed by police officers and died en-route to the hospital.
