I think it is a great idea to meet with the regular teacher as a stepping stone to meeting with the science teacher (it is awesome that your school has a science teacher!). Tell her/him what you posted here, that science is his passion and that he is able and eager to go beyond the current curriculum. I would try to steer the conversation to have a collaborative tone - ask both for recommendations on how to support his interests at home AND in school.
(FWIW, our kids are now in middle school, and we've been able to nurture their interests in science despite minimal help from their schools. (Wordsearches as a science instructional tool in 6th grade? Really?) We provided books (our kids loved "Horrible Science" books - they were reread many times), a steady stream of science related news articles relevant to their interests, science activities at home, science museums, science camps, etc.)
