وَاللّٰهُ تَعَالَى قَادِرٌ عَلَى الْمُمْكِنَاتِ كُلِّهَا
Allah Most High has power over all possible things.
A possible thing is one whose conception does not entail a contradiction. A logical impossibility, such as the same thing both existing and not existing in precisely the same respect, is not a realizable object of power.
Declaring the bodily Ascension impossible would therefore require proof of a genuine contradiction. In the absence of that proof, departure from customary experience does not place the event beyond divine power.