How to enable ssh v1 in MacOS Sierra?
Here's my github repo trying to solve the problem by patching the openssh in homebrew/dupes. It's far from perfect but works.

Basically you have to:

brew tap homebrew/dupes
curl -fsSL https://github.com/boltomli/MyMacScripts/raw/master/homebrew/homebrew-dupes.openssh.diff | patch /usr/local/Homebrew/Library/Taps/homebrew/homebrew-dupes/openssh.rb
brew install openssh --with-ssh1