Will the enemies killed by the explosion caused from Arcane Destruction prolong my Archon duration
No, Arcane Destruction kills do not count towards increasing the time spent in Archon form. I tested by taking my wizard to Iskatu's fight in Normal, building up a lot of shadows and then blasting them by activating Archon form. The resulting timer was still 15 seconds :(.
I actually expected the opposite, but it seems that Arcane Destruction isn't counted among the archon kills for increasing the timer.