What is the theme of Night in chapters 8 and 9?I just need a theme with some evidence of the theme. Thanks.

I think that being able to select evidence from the last
two sections of the work and tie it into a theme is going to be contingent on what the
reader sees as dominant themes in this section.  The theme of utter hopelessness is
something that can be picked up on in these sections.  These are the sections when
Eliezer feels that his father is a burden and the only hope he experiences is the
"freedom" that when his father dies he is now able to think of his own survival. 
Another theme that would be evident in these sections is that of death, in that the
reality of death is the only constant (along with hunger) that accompanies Eliezer. 
There is nothing else except death for him.  Another theme that can be seen in these
closing portions of the narrative would be the dehumanization that became such a brutal
part of the Holocaust.  At this point in the narrative, consciousness is only defined as
a struggle to survive.  Eliezer thinks of nothing but food, bonds of solidarity and
loyalty have been supplanted by the animalistic need to survive, and there is little to
differentiate Eliezer's life from any other animal.  This might be a part of what he is
unable to recognize when he sees his reflection in the mirror at the end of the
narrative.