Xcode 9.2 Beta 1 was released on 31 Oct 2017 and requires macOS 10.12.6+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/Xcode_9.2_Beta/Xcode_9.2_Beta.xip.
The SDKs it contains are:
- iOS 15C5092b
- macOS 17C60c
- tvOS 15K5085b
- watchOS 15S5085b
The compilers it contains are:
- clang 9.0.0 (Build 900.0.39)
- swift 4.0.3 (Build 900.0.71)