You reminded me of my literature classes, Tony.
No, this is not really a metonymy. A very famous example of metonymy is using "throne" for "kingdom." It's actually using one word in the place of another word. The two words might be related in different ways (one might be the attribute of another or, for example, a part of another).
The best term I can think of now to suit your "Einstein" is symbolism
. Einstein is a symbol of someone intelligent or sth.