I borrowed a better DMM today (Thanks to Pelle Nilsson) and measured the voltages with that and everything was fine and as it should be. Mounted the remaining chips in their sockets and right now the board is mounted in the case (sorry, no picture yet). Tomorrow I will try to figure out a good way to connect the ground wire to the chassis and then try the amp for the first time. I wont be using my Denon headphones though, because if there's something wrong I don't want to damage my expensive gear. Instead I will use a pair of old Steelseries Siberia V1 headphones, I don't care if they blow up since they'll never be used again anyways. Hopefully everything will be all right.
I will also continue my search of two M3 bolts and nuts so I can mount the ODAC to the board. And before finishing it all I will need to put some kind of spacer between the board and either the back or the front of case. There is maybe 1mm clearance so the board is going back and forth which is a bit annoying.