Joel 2:25
25 And I will restore to you the years that the locust hath eaten, the cankerworm, and the caterpiller, and the palmerworm, My great army which I sent among you.
KJV
Joel 1:4-7
4 That which the palmerworm hath left hath the locust eaten; and that which the locust hath left hath the cankerworm eaten; and that which the cankerworm hath left hath the caterpiller eaten.
5 Awake, ye drunkards, and weep; and howl, all ye drinkers of wine, because of the new wine; for it is cut off from your mouth.
6 For a nation is come up upon my land, strong, and without number, whose teeth are the teeth of a lion, and he hath the cheek teeth of a great lion.
7 He hath laid my vine waste, and barked my fig tree: he hath made it clean bare, and cast it away; the branches thereof are made white.
KJV
It's definitely NOT... about someone's misspent youth.
The Book of Joel is a prophecy for the end of this world, i.e., tribulation timing.
Revelation 9 continues with more of what those locusts are to do. God tells us in Joel 1:6 that locust army He sends is "a nation", meaning a certain people on earth. He associates a lot of heavy symbology with how they will work upon the earth in the last days, and with stealing the wealth of His people. God is using the natural locust as a metaphor for HOW they will attack His people at the end of this world.
Joel 2:3-9
3 A fire devoureth before them; and behind them a flame burneth: the land is as the garden of Eden before them, and behind them a desolate wilderness; yea, and nothing shall escape them.
4 The appearance of them is as the appearance of horses; and as horsemen, so shall they run.
5 Like the noise of chariots on the tops of mountains shall they leap, like the noise of a flame of fire that devoureth the stubble, as a strong people set in battle array.
6 Before their face the people shall be much pained: all faces shall gather blackness.
7 They shall run like mighty men; they shall climb the wall like men of war; and they shall march every one on his ways, and they shall not break their ranks:
8 Neither shall one thrust another; they shall walk every one in his path: and when they fall upon the sword, they shall not be wounded.
9 They shall run to and fro in the city; they shall run upon the wall, they shall climb up upon the houses; they shall enter in at the windows like a thief.
KJV
When they fall upon the sword they won't be wounded? What does that tell us? It's only symbolic of how nothing is going to stop what God has given them to do in the last days. Only Christ's coming with His great army can defeat them.
They will climb up upon the houses? enter in your windows like a thief? These are all metaphors for the locust army working of Rev.9 during the tribulation. It's about a certain group of men that serve the devil and that will cause deception upon the whole world in the end.