A variation of the military and law enforcement term "ate up", which is a military term used to express someone's uselessness and inability to perform any task.
Also used to express a pointless or chaotic situation such as an
unorganized task where
nobody knows what they
should be doing.
Finally, it is used to describe a hopeless situation.
example#1-Bob: "Hey, I heard Kevin could not score a 280 on
the pistol course."
Fred: "Yeah- he's more 8 up than a soup sandwich".
example#2: Bob: "They want us to complete this assignment by next week, but no one knows who is supposed to be doing what"
Fred: "yeah, that's 8 up"
Example#3: Bob: "Dude, we are stuck
in the middle of the desert, and I just ran out of water".
Fred: "yeah, this is 8
the fuck up"