There are no less than NINE Similes applied to this "locust". Nine characteristics that are applied to this bug, which is overtly evil in nature itself. The Holy Spirit is characterizing these evil beings, just as God’s children are characterized by the 9 fruits of the Spirit in the positive sense.

In addition to that nine times does the Holy Spirit "startle" us to attract our attention to these evil entities. It was not shocking enough to say they are beasts or ugly, because this style lacks emphasis and complete disclosure. So to paint the clearest picture the passage delves into detail about their attributes: power (authority), purpose (torment), shape (horses prepared unto battle), status (crowns), appearance (men), attractiveness (hair of women), viciousness (teeth), defenses (breastplates), & sound (of chariots).

This evil army is "contrary to our experience and known fact" in NINE different ways. We have a figure of speech here nine times over! We can connect the meaning of nine, judgment and fruits of the spirit (which are bad fruit in this case) . The Holy Spirit is declaring judgment over this evil army by choosing 9 figures to apply to them.

So you can see that interpretation is given by using the "tools" of exposition, i.e. figures of speech, word definition and usage, and context. Although the thought conveyed is quite "simple", i.e. to say "an extremely evil army is coming to torment men", the literary devices employed paint a mosaic of copious amounts of information that left unnoticed only distorts the interpretation beyond the original intent of the inspired writing.

Interpretation can be considered simple, when done responsibly with the tools the Holy Spirit employed, which are "the Holy Spirits own markings of our Bibles" (Fig. Of Speech Intro. vi.). Simplicity is achieved when all the pieces are put together and the simple picture emerges from the work. It does not come from carelessness or irresponsible handling of the Holy Scriptures, which results in false conclusions. "Commentators and interpreters, from inattention to the figures, have been led astray from the real meaning of many important passages of God’s Word; while ignorance of them has been the fruitful parent of error and false doctrine." (Fig. Of Speech note)

Saying the Locusts in Revelation 9 really had delegated influence over humans, would be a conclusion drawn from inattention to the following notes on figures used in this passage:

In Rev. 9.3 "And unto them was given power" , the locusts were given power.

(((POWER in Greek : NT:1849   Exousia (ex-oo-see'-ah); from NT:1832 (in the sense of ability); privilege, i.e. (subjectively) force, capacity, competency, freedom, or (objectively) mastery (concretely, magistrate, superhuman, potentate, token of control), delegated influence:  KJV - authority, jurisdiction, liberty, power, right, strength.)))

It is possible that the writer (here the HOLY SPIRIT) may be saying the insect known as the locust, will have actual delegated authority over people,  but remember scripture is only interpreted literally when NO figure is applied.

Verse 3 ascribes Power (authority or delegated influence) to a bug.  This has to be a figure because this "statement appears to be contrary to our experience, or to known fact" (Fig. Of Speech note on figures in general), it must be recognized as a figure, and NOT be interpreted literally. To do so would be ignoring the specific purpose of the figure and miss the "express teaching" shown here.

In the beginning God gave Adam authority over the animals, not the other way around, so this statement, without a doubt qualifies as "out of the ordinary" and departing from "revealed truth or known fact".

This is a known figure, which could be easily identified as Personification,i.e. attributing intelligence to, in this case, an insect.  Bullinger says figures are "a science whose laws and their workings are known"(Figs. Of Speech xi.)

So, you can see how inattentive reading could cause horrible error, with such ideas as that of locusts who become delegates in the parliament or congressional house.  It's an insult to our Father's Word, to translate it into fairytales.  Bullinger compared those who use this type of translation  as a "school boys crib"

On the other hand, attention to these figures would reveal that the "locust army" is one of satan's  high ranking group of evil entities/angels to arrive here on earth, and cause trouble, deception, and confusion.   They accomplish this through their newly given power that acts similar to scorpions, who turn the backbone to mush, paralyzing the victim into submission.  This interpretation reveals the reality of the spiritual world and the beings that exist there.