Tomorrow, When The War Began - Chapter 9

Why, in Ellie's opinion, is Cobbler's Bay and Wirrawee so important to the invaders?
Ellie says that the invaders are most likely using Wirrawee as "a corridor to the big towns and the cities.", as no one would expect Wirrawee to be invaded. As for Cobbler's Bay she mentions that it's a great bay and that the invaders are most likely using it as a port base for ships.

Corrie and Ellie reminisce about how innocent they were in high school and even a few days ago. Why were they still innocent then? Why are they no longer innocent?
They claim they were still innocent then as they still believed that the an invasion would never happen in Australia and that they were safe. Because they now know they are not, they have been torn away from their former innocent without realizing it. The following quote further proves my point as they state "We believed we were safe. That was the big fantasy . Now we know we're not, and like you said, we'll never feel safe again, and so bye- bye innocence."

Why does Homer think splitting up is a good idea?
Again Homer believes that if they split up then if two of them get taken then there will still be three people out there trying to survive and vice versa for three of them being taken. It would also take less time to complete tasks if they did it as a five and, if they're in less number it would be easier to hide from the invaders.

Why do you think the author added a few lines about an Australian jet flying overhead?
Probably to show that there is a possibility of the group being saved and there are people fighting back that might save them. This gives the reader a sliver of hope that everything might be alright.

By blowing up Corrie's house, what does the invading force demonstrate to the teenagers?
It shows the teens that any sign of life or possible 'rebels' in the town will be killed without mercy. The invaders are trying to scare the group off and are also going "We know you're here and we're not afraid to kill you."

Why do you think Corrie reacted the way she did?
Probably cause she just saw her house blow up? And they were just in there? Which means she almost died and the last of what reminded her of her family are gone now? Like I don't know what you expect me to answer here.