As far as I'm concerned, it's 0:0 at halftime. Hernanes is not a football player, and as such I don't consider him a Juve player. Thus, he couldn't have scored a goal for Juve.
Or, at most, since he's always more useful to the opposition, I can consider him a Carpi player and count this as a 1:0 at HT, with an owngoal by Hernanes.