My history teacher told us last semester that some historians think that Joseph (Jesus' after) would not only have been a carpenter, but a master-carpenter due to wether a misinterpretation or mistranslation (it has been a couple of months, so I can't remember). If it were the case, this would mean Jesus would have been raised not a poor, but a rich man, who would have studied with the higher class in society, schools at the time which taught lessons about greek philosophers and roman/greek religions, which could have inspired Jesus for the basics of catholicism.
Have any of you heard about this theory and what do you think about it?
So the basic question you're asking relates to doubt over the meaning of the Greek word tektōn. To start with, it doesn't mean "master carpenter"--there's nothing to suggest it means some sort of super-carpenter. The term is used in classical sources (the LXX, Josephus) to talk about skilled wood craftsmen. But there's no indication that it means some sort of special wood craftsman.
Most Greek dictionaries seem to say it means "craftsman" or "woodworker" or "carpenter". I don't see any reason why it should imply anything about socioeconomic status, other than to note that Nazareth was rather rural, and not a particularly wealthy area.
I don't know what a 'theologist' is, but it's not a strong theory.
As /u/gingerkid1234 has already said the word is tektōn (τέκτων). LSJ, which is a classical, not a koine, lexicon lists its primary mearning as "worker in wood, carpenter, joiner", but does list a sub-meaning "master in any art" with some classical references - to poets and gymnasts. Hardly a definitive argument for 'master carpenter'.
C.C. McCown did a classic study on the word in S.J. Case (ed) Studies in Early Christianity, p173-189. The word in the NT context probably means something a little broader than 'carpenter', so 'skilled craftsman' or 'builder' might be appropriate.
None of which supports the conclusion about Jesus' background being wealthy and educated. We are still talking about a fairly rural setting (Galilee), in which Graeco-Roman education of the sort you mention was not the norm for Jews. Far more likely that Jesus' primary education, whatever there was of it, was embedded in the Jewish religious system. If Jesus was born into an urban centre, and if we had evidence that Joseph belonged to a Hellenising group, then we might conjecture exposure to Hellenistic education models, but that is a large pile of Ifs to start your building upon.