Word for person ahead of time

The best answer is likely to be a synonym for inventor which you mention in your question. Inventor is probably not quite radical enough for your purposes and would exclude people like Albert Einstein and Paul Dirac whose work, although producing revolutionary changes to ways of thought and enabling others to develop new technologies, did not directly involve the production of new objects or materials.

Thesaurus.com suggests a number of synonyms of 'inventor' the most appropriate of which are probably

innovator

pioneer

and

originator

All of the above carry the implication that the work is highly original and disruptive to the status quo so seem to be suitable answers to your question.