If your app is already on App Store, (and your app is not using any features removed in iOS 12.2) yes.
If you are developing your app since now, no. Xcode 9 cannot run your app in iOS 12.2.
You should better also know that you cannot submit apps built with Xcode 9 to App Store.
hi, plz help me about this error?
I always have a problem with my simulator (XCode 9)
It always Failed or could not attach!