Help I accidentally deleted macOS from my iMac!

[Amethyst1]

You need the “Install OS X El Capitan” application.
Does the .dmg or .pkg you downloaded contain that?
If it’s a .dmg, double-click to mount it and check if the application is inside.
If it’s a .pkg, you need to run it (just double-click on it) and the application will be put in… your “Applications” folder.
You can then point your disk creator app (your screenshot doesn’t show the name but you know what I mean) at that.

 

[Fishrrman]

I'm thinking that if the OP is using a late-model MacBook Pro running 10.15 (Catalina), that may prohibit him from creating the installer because he can't "get the necessary files into the right places" without the OS objecting that the El Cap files are too old.
(I could be wrong)

OP:
You said your dad has a Mac Pro, right?
What version of the OS is CURRENTLY running on it?
It MIGHT be possible to get a USB flash drive created on the Mac Pro that will get the iMac running (even if it's not El Cap).
The primary goal should be to get the iMac booting to the Mac OS again, even if it's not El Cap.
ANY version of the OS that can get it running, is better than none at all.

I offer this as a last resort if nothing else works for you:
There are sellers on ebay who will sell you a "pre-built" bootable USB flash drive that has the El Cap installer on it.
Just plug it into the 2009 iMac and it should boot to the El Cap installer.
You'll have to search for these on your own.
You can expect to pay about $20 for one.

With one of these, you can:
1. get booted
2. install El Cap to either the internal drive, OR TO AN EXTERNAL DRIVE (which is what I'd suggest)
3. Get the computer booted from an external drive and then "get to work" on the internal drive.

The business of creating an external bootable flash drive for an older Mac seems to be getting more and more complicated with the newer Macs and OS's.

One other thing:
I'd suggest you get rid of bootcamp and not be foolin' with it in the future.
You see where messing with it has gotten you to right now...

 

[TheMasterOfTech]

Well its been a while but i actually found a 10.6.0 install disc just in a box in my house. its kinda funny how much i tried to get macos back on there when there was just a disc in a random box but whatever. thanks for all the help though