At step 38 I'm measuring the junction at R8 and R9, I assume I am supposed to leave the negative end on J3 pin 2, or do I just measure R8 with the other end of R8.
If not specified otherwise, always measure voltage with respect to ground. In this case, J3, pin 2 is a good reference point.
With both ends of R8 it comes to a little over 27v
This just isn't possible if everything's where it should be. Are you sure you're not missing a decimal point?
and when I measure is with J3 pin 2 it comes to 17.
This is in the ballpark but still higher than it should be. What voltages do you measure at R25 and R28?
Whats wrong?
Generally, it's either poor soldering or incorrectly installed components. Component damage from mishandling or overheating is a distant third. It will take some more measurements to figure it out.