Revert "change minimum SDK to 9"
Revert "change minimum SDK to 9"

This reverts commit 4d9e1c5b5b0cddf47b00d98e0954d6a61df567d7.

wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning