Info isn't always what you think it is.
I retired in 2004 from a fairly large municipal P.D. in southern California after 26+ years all but two spent in patrol. No, not because I had to be in patrol because I wanted to be there. Plenty of opportunities to xfer, all declined. Trained for a couple years until I realized supervision was not listening to me. I preface my comment with this personel employment history to show that I have probably responded to 1,000's if not 10,000's of 911 calls.
As to be careful what you say on 911, of course. Contrary to what other posters say, most 911 systems give the address on the phone your calling from and the name of who pays the phone bill. So, (at least in CA) if you dial 911 and drop the phone on the floor, they will send someone to invstigate a "open 911 call, unknown problem". Other jurisdictions, maybe just the number, kinda depends on how much taxes you paid for your P.D. to invest in a quality syatem. Just before I retired they were testing a system that would connect the responding officers MDT (mobile data terminal) to the 911 call and he could hear and talk to the caller same as the dispatcher. Be aware that the cop responding does not know your house/apt, if you live in the "back" say so, if your "upstairs", say so. If you have dog say so, so the cops don't shoot it. A good dispatcher will ask these things, but good dispatchers (like the one I'm married to) are like good cops kinda hard to find.
As to what to say...Well have you done anything illegal? If you have I'd give my name/address/phone and meet the officer outside on my lawn UNARMED. Say "I feared for my life and I would like to speak to my attorney"
Then he will need an exigent circumstance or a warrant or consent to enter your home, if its your home and not friends or other relatives. Be advised exigent circumstances only have to exist in the officers mind, not yours. I've entered many homes and recovered evidence while the homeowner was screaming at me to leave, and I never lost one in court, becaue I could articulate why I did it.
Now if you havent done anything illegal, do exactly the same. Don't try and explain it, resist the temptation to babble. Do not ever touch anything..leave it exactly as it fell, dropped, or splattered. Unless its your family and its bleeding, do not touch it. I mean it! They will know if you did. No matter how embarrasing. If you were surfing internet porn and had ur pants down and a guy busts you patio door in and you plug him..leave it on the screen. I have testified in more cases than I can remember and the smart-alec who thinks he can shade the truth gets caught, cops included. DA's and juries like honest self depracating witnesses. And whatever you do DO NOT LIE, ever for any reason.
Basically there are two ways to deal with an authority figure, be totally honest, or politely decline to answer and ask for your attorney. Holds true for a traffic ticket or a shooting. A couple of last reminders. You shoot to stop the threat, if the threat stops being a threat, stop shooting. Never, ever shoot for a property crime, no posession is worth a life, even a dirt bags. Loose the smart alec "I'll just drag'em back inside" attitude. It will only cause you grief, trust me I know. Use something big enough to do the job, as my training officer told me, "you only want one version of the shooting, yours"
Get trained, by accredited people. That way you can testify to how seriously you took the posession of a weapon and its use. Rather than "I shoot at tin cans in the backyard".
Don't have anything illegal in the house, guns dope (even a baggy) nuthin! They are gonna search and they will find it, metal detectors, dogs, you name it. Be a good neighbor. The cops are gonna canvas the neighborhood and interview everyone. If you talk tough about guns and "what your gonna do" it will haunt you in court. They will track your last addresses and contact those local cops and with all the CAD systems (computer aided dispatch) they will know if a neighbor 12 years ago called in another city-state whatever, on your loud stereo and that guys name/add/phone.
Lastly, YOU WILL BE SUED I promise you. Even if the DA clears you and gives you the local assist the police medal. I promise you. Everybody and I mean BODY is attached to someone, the coroner will find them. They will get the cause of death. They will get a contingency fee lawyer who has a P.I. working for him (prob a retired cop) who will find out what you own and sue you for it. Remember civil juries only need 51% not beyond reasonable doubt. They know you have homeowners insurance and they want a settlement. A photo of the dirtbag you shot in his boyscout uniform when he was 12 blown up to poster size will sit staring at you during the trial.
All that said, all those dire predictions, would I still shoot? If forced to yes. But I would not enjoy it. And it would have to be as a last resort. Ask any cop (a real one w/more than 5 minutes experience PLZ) who has ever been involved in a shooting if he wants to do it again, ask a vet who's been in combat. If they tell you the glory of shooting another human being, they need counseling.
Yes, just before I retired I was involved in a shooting. No I did not shoot but a man lost his life right in front of me and it did not need to happen. He did not deserve it, he'd done nothing wrong. He died because someone close to him lied to the police. Simple as that.
Don't look for it, if your forced to shoot/act some-how, be reasonable and get to your attorney ASAP. The cops are not your enemy or your friends, they are the government and they have a job to do, do not hinder it, but if your the "suspect" don't help them either.
Be safe, lock your doors/windows have security lighting, let your 117lb Rottweiler sleep on your bed and keep that 12ga pump with the light attachment next to the night-stand. No guarantees but keep the odds on your side.