What Grade is This?

We've been doing great this past month.  Slowly but surely learning what works for our school and what doesn't.  For instance most of the text books that we got were for 1st grade and they weren't challenging enough by half.  So we turned some of them back in for 2nd grade materials or we just ignored them and did some unschooling for the subject.  For instance of Monday we went whale watching.  We learned about baleen whales vs. toothed whales.  We discussed what both types of whales eat and how they go about catching their prey.  Also discussed the classification of whales as mammals.  We never touched a text book but we sure did learn a ton.  We'll work on whales, expanding our knowledge, for the rest of the week.  Next week we'll move onto whatever else catches our fancy. 

What worries me about this is that when we move in June I either need to continue homeschooling or convince his next school to test him for grade level placement.  Because honestly at the pace that we're going he'll be done with 2nd grade at the end of the summer.  September being 7 months from now that's plenty of time to cover all of the material.  The other issue is that even if they test him would it be right to put an almost seven year old in class with a bunch of eight and nine year olds.  That seems like a recipe for bullying. Maybe a Montessori or Waldorf school would be better but I'm not sure that we could afford the cost of tuition to a good one.