Have played this game near-constantly since 2015, on Android, and just today got an iPhone. I tried linking new device to facebook to pull up my linked account, which i had read was the way to go about it, but I keep getting Error Code 9.0 and am unable to grab it. I would be absolutely devastated to lose everything but am frustrated trying to get it to work to no avail.
The Facebook linking feature is currently disabled. See the official announcement here: Facebook Linking Temporarily Removed
Please get in touch with our Customer Support, they should be able to help you out with it.