It is fixed i travelled every 15 days for business reason everytime it comes on 8th pf i m fully sure because Bangalore station 8 to 10 goes via yeswanthpur to belgaum pune yelhanka hubbali vasco etc and in between 7 30 to 9 only 2 trains go via yeswanthpur that is 1st Bangalore rajdhani and 2nd belgaum and the other trains goes after 9 30
At rare cases it arrives 9 very rare
99.9 it comes on 8th pf