you on fccuk?
i cant think of any thing over the passenger side, gearbox oil?
the squeel will most likely be the alt belt tensioner, probably best replace it before running it any more if its loud, cos if the belt jumps off very usually it goes and jumps into the cambelt.
and 9psi seems very low boost, they run more like 14-15psi standard, hope its not hiding a slipping clutch!