Updating iOS 8.4 to iOS 9 problem?

HI guys, i have a problem with my iPad 4 when i accidentally press the software update button, i dont know anything about updating an iOs, my Current Ios version is iOS 8.4 after i press the update button i thought everything would be fine but then it stuck on one image saying that i need to connect my device to iTunes, but before i connect it to my iTunes i did some reseach about how to update iOS 8.4 to iOS 9. And got some answers so when im trying to connect my iPad to my iTunes something wrong happen, my iTunes can't detect my device and my device is keep restarting like it will restart and then it will show the same image saying connect to iTunes and it will restart again. I really dont know what to do, i have some information on how to update but im stuck on the very first step, please help me with this.

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