Fine, let's just say that you are right and the NAB is the best translation and that particular verse (Isaiah 9:6) does not mean Jesus is God. Let us look at another verse in the NAB then:
Philippians 2:5-8- Have among yourselves the same attitude that is also yours in Christ Jesus, Who, though he was in the form of God, did not regard equality with God something to be grasped. Rather, he emptied himself, taking the form of a slave, coming in human likeness; and found human in appearance, he humbled himself, becoming obedient to death, even death on a cross.
Right here even this "best translation" admits that Jesus is Divine and died on the cross. The NAB is a Catholic version. Catholics believe Jesus is the Son of God.