Can I install iOS 9 on my iPhone / iPad / iPod touch?

Apple announced at WWDC 2015 that iOS 9 public beta would launch in July. For those with older devices, the good news is that any hardware capable of running iOS 8 will also be supported by iOS 9. This means that when the firmware officially releases in the fall, the following devices will be compatible with the update:

iPhone 4s
iPhone 5
iPhone 5s
iPhone 5c
iPhone 6
iPhone 6 Plus

iPad mini
iPad mini 2
iPad mini 3

iPod touch 5