oldhenry - that 9mm Ruger Officer's Model will serve you well. The 3.6" barrel may not be the best configuration for shooting steel chickens at 50 yards
but I suspect that's not why you selected that gun.
It appears that you wanted a single action semi-auto and if you're proficient with that platform then it will serve you well.
As for a self-defense cartridge, you're going to get a phone book worth of suggestions, many of which will start with, "I use X".
Just because someone else uses "X" doesn't mean that "X" is right for you.
I will tell you based on actual street results, some 9mm loads have very good track records. The longest track record is probably the Federal 9BPLE round. The 9BPLE round doesn't always expand but it does feed well in most pistols and it generally penetrates well even when it doesn't expand. The Illinois State Police was one of the first LE agencies to go to the 9mm and they have a long history with the 9BPLE round. (the 9BPLE is rated +P+ in some loadings but not all)
The old Winchester controlled expansion rounds also have a long track record and generally do expand reliably, however the +P+ versions can be hard on pistols and I would avoid them in large quantities. The current Ranger SXT line has shown good results in actual shootings. Despite the hype, the 9mm Silvertip didn't always work as advertised.
There is no shortage of 9mm self-defense ammo on the market. Everyone makes something in that popular cartridge but a hollow point that has a pretty package and self-serving hype isn't necessarily the best self-defense cartridge. Not saying they are bad but I am saying that marketing isn't the same as actual performance.
As I said earlier, your criteria should be: flawless functioning, good penetration, reasonable terminal performance and accuracy.
115-125 grain 9mm bullets rarely have problems penetrating and in fact often penetrate very well unless the hollow point opens too quickly. I would strongly advise against the 147 grain bullets in any self-defense situation, they have an horrible record in the real world. They were designed for suppressed guns and that's where they belong.
Good Luck
P.S. Still digging that motorcycle in your avatar !