Can Touch ID unlock a personal SSH key?
Update:

One option is add your private SSH key to macOS Keychain, then use TouchID for Keychain authentication. You will want to use ssh-add -K ~/.ssh/[your-private-key] -- however on macOS 10.12 Sierra the feature needs to be enabled by editing editing ~/.ssh/config and adding:

Host * (asterisk for all hosts or add specific host)
   AddKeysToAgent yes
   UseKeychain yes
   IdentityFile &lt;key&gt; (e.g. ~/.ssh/userKey)


For details, read:


Permanently add your private key to Keychain so it is automatically available to SSH
Saving SSH keys in macOS Sierra keychain 


Original:

At present TouchID unlocking of an SSH key is not available for macOS.


The sudo-touchid Xcode project demonstrates how to build a command line application that is TouchID enabled and fails over to a passcode dialog. It runs on the 2016 MacBook Pro with Touch Bar. However, it is for sudo, not ssh. This indicates that the idea is technically feasible.
The Prompt 2 SSH client has TouchID support -- for iOS, not macOS. This indicates that comparable applications might become available from commercial developers.
One developer online started an ssh touchid wrapper project a few months ago -- although it is an empty project stub. This indicates that others may be asking a similar question to yours.