Programming my ATmega8 board using Arduino IDE
I haven't verified the mapping but I know that this line will cause you an issue:

Button_Status_J6=digitalRead(Button_Status_J6);


Here you are basically overwriting your mapping to digital pin 10, returning the result of the digitalRead into the variable Button_Status_J6, which will become either 0 or 1 on the first read.

At the top of your code, you would need to set-up another variable to read the result of the digitalRead:

int Button_Status_Read=0;


And then use it to read digital pin 10 (Button_Status_J6):

Button_Status_Read=digitalRead(Button_Status_J6);
Serial.print("BUTTON 6 STATE IS   =  ");
Serial.println(Button_Status_Read);


EDIT

The other issue was that the wrong clock source was selected for the fuse setting "SUT_CKSEL". When using an 8MHz external Crystal the following clock source needs to be selected:


  Ext Crystal/Resonator Medium Frequency


To start with, it is recommended to choose the option with the maximum start-up time ("16 CK + 64ms") to ensure the crystal oscillation has enough time to stabilize. After validation, faster start-up time can be selected.