I have an iMac(Early 2009) running Leopard (10.5.8). Now I want to upgrade my OS to El Capitan (10.11).

The situation is this one:

✔ my iMac version is listed under the upgradable devices

Apple makes it fairly difficult to do a clean installation of OS X on a Macbook, primarily by providing misleading completely false instructions in their help. If you make a new account (e.g. For a work laptop), you should try to sign into it in iCloud and the App Store on the laptop, if possible, before reinstalling the OS. Before starting the installation, you need to download Mac OS El Capitan iso image and unlocker 208 from the links below. Download Mac OS El Capitan(Google Drive) Download Mac OS El Capitan(Utorrent) unlocker208. After the downloading finished, extract them then install VMware from here, that’s ok if you have installed before.

When finished, OS X El Capitan will boot into a brand new clean install, running through the initial OS X setup process on the Mac as if the Mac was brand new. No files, no data, nothing will be on the Mac except for what comes with OS X El Capitan, that is what a clean install is for.

✘ MacOSX 10.6.8 is required to be installed (due to Mac App Store introduction) on the iMac

Official solution (or what I undestood reading Apple website)

• buy the DVD of Snow Leopard (10.6) from online Apple Store and install it on 10.5.8;
• update the OS until 10.6.8;
• use the App Store to download and install El Capitan.

Said that, after some search, I found this macworld article showing alternative methods to upgrade from 10.5.8 MacOSX version to a more recent one. This reading brought me to another solution:

Clean Install El Capitan

Alternative solution

• use a Mac of a friend of mine which runs El Capitan to download El Capitan from Mac App Store;
• create a bootable usb stick from it;
• use it to do a clean install on my iMac (erasing all disk content before choosing the HDD in which to install El Capitan)
• configure my iMac creating my Apple ID

Questions

1. Will solution 2 work?
2. Is solution 2 legal?

Install El Capitan Without Apple Id Free

Note

The linked article hit my questions' topics but I did not deeply understand nor the configuration of the Apple ID on the fresh installed El Capitan nor the legal aspects of the solution.