Isaiah 9:6
6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace.
Jesus is called the "mighty God" and "everlasting Father".
The controversial titles given to the child in this passage are "The mighty God", and the "everlasting Father". Some interpret these as being theophoric names, essentially making a statement about God, such as, "The Mighty God (is) the everlasting Father". The REV translates the titles as, "The Mighty God is an Extraordinary Advisor, The Everlasting Father is a Ruler of Peace". Such names are given to people in Scripture, in order to honor God. For example, the name Hezekiah literally means something like, "Yahweh strengthens". There are many such theophoric names in Scripture - even Jesus's name is theophoric, and means something like, "Yahweh is salvation", or "Yahweh saves". So, one way to understand those titles in particular is that they are given to the Messiah, to honor the Father.
Suppose, however, that Jesus is called "The mighty God" here. This, by itself, would not be enough to conclude that Jesus is God, because being called "God" in Scripture does not by itself mean that someone is Almighty God. Sometimes in Scripture, terms that can be translated "God" are applied to human judges, rulers, powers, or angels (Exodus 7:1, 21:6, 22:8-9, Psalm 82:1, 82:6, 97:7: 2 Corinthians 4:4), as explained by Jesus in John 10:33-36. Jesus being called "God" would, in this case, be designating Him as a ruler, though He would be a "God" who Himself has a God, as Psalm 46:6-7, which is applied to Jesus in Hebrews 1:8-9, teaches (under the most common Trinitarian understanding of both passages).
The term "Everlasting Father" or "Father of the age", "Father of eternity", etc., is less clear, and can be interpreted in many ways from both a Unitarian and Trinitarian point of view. Clearly, Trinitarians do not believe that it means that Jesus is the Father, but rather, the creator of something new - be it the Genesis creation, the new creation, the coming Kingdom of God, etc., and Unitarians could propose similar suggestions, especially those who hold to a pre-existent view of Jesus, and believe that God created the universe through Him.