Can I connect a boost gauge to that line, does it actually produce vacuum?

Or the only possible way to connect the boost gauge is to buy the vacuum adapter?

I saw a vacuum line coming out of the turbo, am I right?

 

no, you need to get your vacuum source from the intake manifold; It's possible to take it from other places, but such as you've circled, are a long way from the intake & on the other side of control solenoids and cannot be relied upon for any sort of accurate reading.
(sorry for the run-on sentance)

 

noope, I tried tapping into that line to install a boost gauge thinking itll work but if I can remember it only read vacuum, not boost =\

 

That line comes right off the turbo and its a pressure line. It will not read vacuum because the pressure in that line is always higher than the intake manifold under an off boost condition.

When your turbo hits x psi, that line opens the waste gate.