AH yes.. the good old misunderstanding of Isaiah 9:6 (or 9:5 in the Hebrew numbering).
That is the royal name of Hezekiah. There are plenty of incidence and examples in the Jewish scripture where people's names describe traits in God, and Hezekiah literally means 'God is our might'.. so.. that's just one of the list of his royal names , from a historical point of view.
No need to shove prophecy into that.