It's here. You can now download iOS 9 on your iPhone, iPad or iPod Touch. The latest version of Apple's mobile operating system will run on any iDevice from 2011 or later. That means if you have an iPhone 4S or later, an iPad 2 or later, or a fifth- or sixth-generation iPod Touch, you are good to go.
There are two methods that can be used for updating, but before we get started, be sure to check out CNET's guide for preparing your device for the update.
Method 1: Over-the-air update
Make sure you are connected to Wi-Fi and running the latest version of iOS -- iOS 8.4.1. Then head to Settings, select General, followed by Software Update and click the Download and Install button.
This method is definitely the easiest, but it could take a long time. On major launch days like today, Apple's servers can become overwhelmed by the number of users attempting to update their devices.
Method 2: Updating with iTunes
Sometimes it can be faster to downloaded and install the update through iTunes on your Mac or PC. You will need the latest version -- iTunes 12.2.2 -- to do this. To check for iTunes update, open the program, click the iTunes menu and select Check for Updates.
Once iTunes is up-to-date, it's time to connect your iOS device to the computer using the lightning charging cable. Next, click on the iPhone device logo in the top-left corner, tap the Update button, followed by the Download and Update button. (You can also opt to use the Download Only option to download the update now and install later.)