Unfortnately, they are not yet available to mere mortals. :) Stu probably has it in his OS test versions of the OS.
Apple Says 'KRACK' Wi-Fi Vulnerabilities Are Already Patched in iOS, macOS, watchOS, and tvOS Betas (http://www.macrumors.com/2017/10/16/krack-wifi-vulnerabilities-patched-apple-ios-macos/)
The key word there is ?eta. The comments in the article are probably as helpful as the article, IMHO. Look for a OS Security and possibly a hardware update for all of your devices, soon.