I took the safe route also going with an under construction policy through Falcon insurance. For the $250 per year fee it's a piece of mind thing.
If theres a fire or theft I know there wont be any issues and I'm covered. My homeowners policy also has a blanket section that says it covers contents but the small print in the exclusions for the policy state that aircraft are not covered. I had to specifically ask for a copy of the exclusions on my policy.
If you look at the Bill of sale for your kit I'm guessing it reads the same as mine calling it an airplane. Good luck trying to get a home owners policy to pay for that.