Question: In Revelation 12:12, we have this passage “Therefore rejoice, you heavens and you who dwell in them!” Heavens is the universe, so who dwells in it? Could God create other intelligent beings in our cosmos?

Also in this passage “You have made heaven, the heaven of heavens, with all their host... The host of heaven worships You.” (Nehemiah 9:6 ESV) it seems again it talks about some other beings, not angels.

Answer: 
There are numerous references to other beings "in the heavens" or outside the earth as we know it such as:

* 1 Kings 22:19 - Micaiah continued, “Therefore hear the word of the LORD: I saw the LORD sitting on His throne, and **all the host of heaven** standing by Him on His right and on His left.
* Neh 9:6 - You alone are the LORD. You created the heavens, **the highest heavens with all their host**, the earth and all that is on it, the seas and all that is in them. You give life to all things, and the host of heaven worships You.
* Job 1:6, 2:1 - One day the **sons of God** came to present themselves before the LORD, and Satan also came with them. ... On another day the **sons of God** came to present themselves before the LORD, and Satana also came with them to present himself before Him.
* Job 38:4, 7 - Where were you when I laid the foundations of the earth? ... while **the morning stars** sang together and all **the sons of God** shouted for joy?
* Ps 33:6 - By the word of the LORD **the heavens** were made, And **all the host of them** by the breath of His mouth.
* Isa 34:4 - All the **host of heaven** shall rot away, and the skies roll up like a scroll. All their host shall fall, as leaves fall from the vine, like leaves falling from the fig tree.
* Isa 45:12 - It is I who made the earth and created man upon it. It was My hands that stretched out **the heavens**, and I ordained **all their host**.
* Luke 2:13 - And suddenly there appeared with the angel a great **multitude of the heavenly host**, praising God and saying:
* Rev 12:12 - Therefore rejoice, O **heavens, and you who dwell in them**! But woe to the earth and the sea; with great fury the devil has come down to you, knowing he has only a short time.”

[Note: the word "host" in the OT is צָבָא (tsaba) and means "army, war", etc.]

Note that whoever these beings are that inhabit the heavens, they are called by various names such as:

* "host of heaven"
* "multitudes of heaven"
* "sons of God"
* "morning stars"

Such beings presumably include angels (cherubim and seraphim and others?) and possibly others whose identity, function and characteristics are never stated. The closest we get to a description of the throne room of heaven is in Rev 4 & 5 (presumably symbolic) where we have several classes of beings all praising God. [It appears that Satan came from among these heavenly creatures as hinted at in Isa 14:12-15, Luke 10:18, Rev 12:7-12.]

Further than this we cannot go.
In order to understand the "who", we need to look at the context to understand the "where".

First, let's look at the word "heaven(s)" in the original languages.

**Hebrew שָׁמַיִם *shamayim* ([Strong's H8064](https://biblehub.com/hebrew/8064.htm))**  

Brown-Driver-Briggs defines it as:

* visible heavens, sky, where stars, etc., are
* rarely of angels
* before which fowl fly
* as abode of God

**Greek οὐρανός *ouranos* ([Strong's G3772](https://biblehub.com/greek/3772.htm))**  

Thayer's Greek Lexicon defines it as:

* the vaulted expanse of the Sky with all the things visible in it
* "the region above the sidereal heavens, the seat of an order of things eternal and consummately perfect, where God dwells and the other heavenly beings" in [2 Corinthians 12:2](https://biblehub.com/interlinear/2_corinthians/12-2.htm)

The topic of "[Heaven](https://wol.jw.org/en/wol/d/r1/lp-e/1200001949)" in the *Insight on the Scriptures* gives a fuller definition of the concept that corroborates with both BDB and Thayer.

Within the context of Revelation 12:12, this is the spiritual realm where Jehovah God, Michael the archangel, all the other angels (including Satan the Devil) are located. In vss 7-9, we see Satan being cast out of heaven and therefore those "who dwell in them" would be spiritual beings (Jehovah, Michael, angels) that are righteous and faithful.

Jeremiah 9:6 breaks down "heaven(s)" into different locations:

* "made heaven", most likely the physical sky
* "the heaven of heavens", the spiritual realm

At the end of the verse, "the host of heaven" seems to be somewhat ambiguous. Different translations have different wording:

* *the angels of heaven*; New Living Translation
* *the heavenly lights*; New American Standard Bible
* *the stars of heaven*; Christian Standard Bible
* *the companies of Heaven*; Aramaic Bible in Plain English
* *praised by the stars that fill the heavens*; Contemporary English Version
* *The heavenly powers*; Good News Translation
* *the army of heaven*; International Standard Version, New Heart English Bible, World English Bible

The Hebrew word צָבָא *tsaba* ([Strong's H6635](https://biblehub.com/hebrew/6635.htm)) is used which is defined as army, war, warfare. So Jeremiah is most likely speaking about angels worshipping Jehovah God.