Been said before:
1) any gun can be a home defense gun. We just think we have to have a reason to buy more guns.
2) after the novelty wears off, the big handgun they were trying to use as EDC will be left in the bedside dresser drawer.
Been asked by others the same question, since I’m the “gun guy” around here. My response is to tell them to go get a 1#, 1.5#, and 2# dumbbell and carry them around and see what they are willing to live with. Almost all asked for something lighter than the 1#! And I understand. These are not Tier 1 operators, just non gun folk (or they wouldn’t be asking me) wanting to carry for the first time. And they are not going to buy a lot of gear, and certainly not top of the line “must have” gear. Best that most will do is put a box or two through their pistol when they buy it and maybe another box every month if so. My starting place is always a Taurus 856 in a 2” or 3” model. Buy some snap caps and “shoot” the bad guys on tv until you can pull the trigger and the front sight doesn’t move. About the most practice any of them will do, if they do that.
Still a heavy pistol for carry, compared to and Airweight or LCR, but the 856 is more manageable of recoil and can be carried still. Some that I have helped have gotten G42, cause they like mine since it’s lightweight and small enough for pocket of purse carry. Others have actually spent money and gotten a SW 637! LOL Had a couple of ladies choose a LCPII in 22lr, and they actually use quality ammo and practice alot. I don’t worry about them since I also trained their protection dogs they take everywhere with them as well. So they actually carry, so good for them.
My home defense arsenal is a four single shot 12ga Toppers and three G3Xs scattered around the farm. Sold all of my Glocks, except for my 42 and 43, when they were worth something and moved until the G3 series since they started making them without a safety. So my answer for the OP’s question is a Taurus G3 in some flavor if forced to go 9mm. The G3C is now a without a safety, and it’s a nice carry pistol, but still too big for me. If I feel the need to take a 9mm, I take the GX4.
Lefty