please help! i will mark brainliest!

Answer:
(-4.5, 0)
Step-by-step explanation:
I don't even use midpoint formula for these types of problems, we can just count and see where they meet in the middle.
0 --- (-9)
(-1) --- (-8)
(-2) --- (-7)
(-3) --- (-6)
(-4) --- (-5)
(-4.5) --- (-4.5)