Did you watch until the end? It was smoke and it was coming down steeply from a high altitude. The smoke was very thick in the higher altitudes.
Rocket exhaust could leave smoke but a jet contrail is just water vapor. Plus a rocket’s travel would be over once it exploded not continuing on for miles afterwards.
You can’t tell up or down, coming or going with contrails or rocket exhaust.... Very misleading .. Like Chinese “ICBM” off Los Angeles. Was just jet contrail in light of setting sun.