I think the expression you could use is "he knows the way from being a shy adolescent to a professional ..."
'the way' means 'the path'. So 'I know the way to the restaurant without getting stuck in traffic'.
If you say 'I know the way' it means 'I know how to get there'.
There is no such expression as 'knows all the way', this is mixture of different expressions 'he knows all the ways to develop from a shy child into a confident professional' - this would be appropriate to describe a teacher who knows many different ways to achieve something. The second expression is 'he has come all the way from being a shy child to being a confident professional'
'Come all the way' is used to emphasise where someone has come from. E.g., 'John has come all the way from Timbuktu to speak to us today'.
Personally although I would say 'he knows the way from being a shy adolescent' is correct, it's not ideal style, because it implies that John's experience is valid for everyone, whereas what we are really saying is that John has come from this background and overcome a lot of difficulties, so it would be better to say
'He has come all the way from being a shy ...'. If we wanted to talk about the lessons we could teach others we could talk about that in terms of himself. 'He has learned how to overcome shyness' and maybe follow that up with saying how he helps others ', and now he teaches others.'