All mobile operating systems have to be built for the specific model - there's no generic build you can just install on any phone. It's highly unlikely that Wiko will produce an Android 9 update for this phone (a two-year old budget model will rarely get any support - that costs the manufacturer money, and margins on such a phone were low to start with, so it doesn't make sense for them). Which means that the only possibility is if someone has made a custom ROM based on Android 9 for this device.
If they have then they'll probably be able to tell you how to root the phone and install it. But it's a big "if": ROM developers tend to be enthusiasts, so tend to target higher-end and more popular phones. So I'd definitely find out whether such a ROM exists before worrying about how to install it. To be honest I don't think it likely.