k9s plugin for the asdf universal version manager.
asdf plugin-add k9s https://github.com/twuni/asdf-k9s.git
Then, manage k9s versions just as you would any other asdf plugin.
For example:
# Install the latest version of k9s
asdf install k9s latest
# Set your default k9s version to the current latest version
asdf global k9s latest