Wireless with 802.11r, 802.11k and 802.1x
As of 10.13.6 macOS doesn't support 802.11 v, k or r but interoperates with APs that have it enabled.
https://support.apple.com/en-us/HT206207
https://framebyframewifi.net/2017/08/20/macos-wi-fi-roaming/
EDIT: No change (e.g. no support) in 10.14 Mojave.
EDIT 2: Still no support in 10.15.
I found the answer for anyone who is interested.
According to this thread, no support for 802.11r/k for Os X up to 10.9:
https://supportforums.cisco.com/discussion/12314591/8021r-and-fast-roaming