When I update iPhone 6 with iTune it show me error 9, how could I do? please help.

Check your security software settings, to allow contact to Apple servers:

Related errors: 2, 4, 6, 9, 1000, 1611, 9006. Sometimes security software can prevent your device from communicating with either the Apple update server or with your device.

Check your security software and settings to make sure that they aren't preventing a connection to the Apple servers.

copied from Resolve iOS update and restore errors