“And the fifth angel sounded, and I saw a star fall from heaven unto the earth: and to him was given the key of the bottomless pit. And he opened the bottomless pit; and there arose a smoke out of the pit, as the smoke of a great furnace; and the sun and the air were darkened by reason of the smoke of the pit.” Revelation 9:1–2
The first thing to note is that the star that fell from Heaven onto earth is an Angel in good standing with God, not a fallen Angel or demon. This Angel was in Heaven and came to earth. Secondly, the key that this Angel has was in Heaven not on earth, and the bottomless pit is a physical place located on earth.
“And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand. And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.” Revelation 20:1–3
The Angel with the Key to the Bottomless pit could be the same Angel in both Revelation 9 and Revelation 20, but there is no biblical account that differentiates them, anything more than this would be guess work or supposition.