J.P.
"We don't know what we don't know" something a good friend once told me.
After consulting my doctor about my son's fits, both doctors agreed to ignore him and let him work it out. If we try to comfort them or work through it with them it reinforces the negative behavior.
Also, do you have to work? Maybe if there is someway around it you could stay home a bit longer as he may miss you and this is why he is acting out.
I babysit for two airline pilots and over the year he has come to realize what it means when they bring him over. He's had a dramatic personality change and everytime it gets worse. That started at about 9 months for him as well. He is 1 1/2 now.
~J.