Q: the Iphone 5 could not be updated. An unknown error occurred (9).

Hi TINTIN2893,

Thanks for using Apple Support Communities. Based on what you stated, it sounds like you are receiving an error code when trying to restore the device. I would recommend that you read these articles, they may be helpful in troubleshooting your issue.

Resolve iOS update and restore errors in iTunes - Apple Support

Get help with iOS update and restore errors - Apple Support

Related errors: 2, 4, 6, 9, 1611, 9006. Sometimes security software can stop 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 blocking a connection to the Apple servers.

If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

Cheers,

Mario