Answer 1

No. IOS apps are written in Swift or Objective C. There are some cross platform systems that allow you to write in C# or Javascript but those are considered somewhat marginal by experienced iOS developers.

You need Xcode IDE (even with the cross platform systems) and Xcode does not support Kotlin. Kotlin is intended for use with Android systems. So far, you can’t write Android software in Swift or Objective C either. (Although since Swift is open sourced, there are some experiments being done with Swift on Android, but it is nowhere near a production thing.)