Yes certbot-auto should work on Raspbian 7 but note you'll need a large swap file enabled in order for it to succeed at building the recent version of python-cryptography that it depends on:

https://github.com/certbot/certbot/issues/1081

This is resolved by .deb packages; they're available in jessie-backports, but I'm not sure if/when those will ever make it to Raspberry Pi land.

Should be able to!