my zj randomly quit starting with the key

I dont exactly daily drive my jeep me so it sat for 2 or three days. Today i hoped in it trying to run to the store right quick but i turned the key and "click click click" she went. I thought it was a dead battery from sitting so i put it in reverse and let it roll back and dropped the clutch fired up just fine and ran like always. Went in to the store for a sec. Came back out and same thing now i wondering "wth". So i roll start it again and it ran just fine home. Now i want to figure this out so i turn the jeep off and and try to start it again now the dome lights and gages are acting funny. Turn the key all the way, nothing. I turn it on and off several times to see if maybe something that will point me in the right direction will happen. now when i try to start it all of the electrical flat lines and come back on and flickers the battery gages flat lines and come back up to just over 9. I hook up some cables to my buddys car to see if the battery could be it but no change, tried tapping on the started, nothing. Starter relay is clicking and every now and again it sounds like the starter "tries" to turn but it doesnt. Just to test if something is wrong somewhere else i roll start it one more time, fired right up, and everything works as it should. Im stumped...

my zj randomly quit starting with the key