ExBethelite, I guess one can say with certainty that Apollyon/Abaddon does not refer to Jesus, if you follow the analysis of the original words. I agree with EasyPrompt. Satan is a good contender for the title. Here's a few thoughts on the abyss.
The abyss can be
favourably compared to the realm of the dead (Rom. 10:7; cf. Luke 8:31). In the
abyss = inactive. Out of the abyss = active. God allows the beast to come up from
the abyss (Rev. 17:8, 9, 11; cf. 11:7, 8). As part of the fifth trumpet blast,
a star (or angel) unlocks the abyss, unleashing a locust plague to torment
mankind. The angel does not control the locusts. Apollyon/Abaddon is their king. These are the soldiers of the beast, sent out to control and subdue
the masses (Rev. 9:1-11; cf. 11:7, 8). Later Satan the Devil would be
sealed in this abyss (of inactivity) for a thousand years (Rev. 20:1-3).
EasyPrompt, I agree with the first part of your explanation, but you lost me with the second part. Why would the locust-scorpions attack religious institutions, starting with the Bethels? They don't distinguish the religious or non-religious. The only ones that's exempt are those with God's seal (Rev. 9:4). All others will be tormented, perhaps by taking away their freedom? [[βασανιστής, οῦ, ὁ torturer, jailer Mt 18:34 uses βασανίζω of the treatment of a debtor from whom everything possible is to be exacted.* See BDAG.]] This will only take place for five months as the fifth trumpet or first woe. According to my reckoning this is part of the first half of the tribulation. Where do you get your 3 1/2 years?
Apollyon: Rev. 9:11(the locust-scorpions from the abyss) ἔχουσιν ἐπʼ αὐτῶν βασιλέα τὸν ἄγγελον τῆς ἀβύσσου, ὄνομα αὐτῷ Ἐβραϊστὶ Ἀβαδδών, καὶ ἐν τῇ Ἐλληνικῇ ὄνομα ἔχει Ἀπολλύων. Ἀπολλύων is a translation and personification of אֲבַדּוֹן (→ Ἀβαδδών, 4:11) “destruction,” for which the LXX uses → ἀπώλεια. It means the Exterminator or Destroyer. As seen, from the time of Grotius it has usually been taken as a play on Apollo, which is the actual reading in Syph.[1] From the time of the victory of Octavian at Actium under the temple of Apollo which was later enlarged by him, Apollo was especially regarded as the god of the empire. The locust is his creature. However, such an explanation muddies the water. What should be kept in mind is that the book of Revelation was written by a Jew and has a predominantly Semitic background. The origin of the Hebrew name Abaddon should bring us closer to what John meant.
Abaddon: Αβαδδών, ὁ indeclinable אֲבַדּוֹן) Prov. 15:11; Ps. 87:12; Theodotion Job 26:6; 28:22=ἀπώλεια LXX). Abaddon, name of the king of the abyss Rev. 9:11, explained as Ἀπολλύων, i.e., Destroyer ) cp. (אָבַד. With this nuance of ʾabhadh we come to the most important noun from this root, ʾabhaddon (with its by-form ʾabhaddoh). Very rarely does this word mean “destruction” (Job 31:12; perhaps also in 1QM fragm. 9:3). Much more often in the Old Testament, and particularly in Wisdom Literature, it means the “place of destruction,” i.e., the Underworld. However, in Rev. 9:11 it is used as a personal name, so this meaning should be ruled out. See BDAG.
ʾabhadh is used in a more general way for destruction of enemies in political and religious conflicts (2 Kings 10:19; 11:1; 19:18; Jer. 46:8; cf. also Jer. 40:15 and the Mesha Stela, cf. H. Donner-W. Röllig, Kanaanäische und aramäische Inschriften, 3 vols. (Wiesbaden, 21966–69, 31971–76), and for ill-treatment of the people by kings and princes (Jer. 23:1; Ezek. 22:27)—all in the piel; cf. the qal in Jer. 10:15, and the Aramaic peal in Jer. 10:11).
Finally, ʾabhadh in the qal exhibits a variety of nuances: Quite often the qal form means simply “to die.” However, the context rules this meaning out. The sting of the locust-scorpions cause pain but do not kill. Of greater theological significance is the use of this word in prophetic texts where the verb describes how in critical times, when evil increases, good attributes and positive ideas vanish (truth: Jer. 7:28; knowledge of the law: Jer. 18:18; Ezek. 7:26; wisdom and good counsel: Is. 29:14; Jer. 18:18; 49:7; Ezek. 7:26; cf. Ps. 146:4; Deut. 32:28 and Damascus document A, i.e., CD A 5:17; righteousness: Mic. 7:2; courage: Jer. 4:9; etc.). The two plainly stereotyped expressions “the place of refuge (manos) is lost,” i.e., there is no place of escape (Am. 2:14; Jer. 25:35; cf. Ps. 142:5[4]; Job 11:20), and “hope (→תקוה tiqvāh) is lost” (Ezek. 19:5; 37:11; cf. Ps. 9:19[18]; Job 8:13; Sir. 41:2; 11QPsa 22:8; etc.) should also be included here.[3]
[1] Syph = Syro-Philoxenian Version, derives its name from Philoxenus or Xenayas, Bishop of Hierapolis in Syria, A. D. 488 — 518, who employed his rural bishop Polycarp to translate the New Testament from the original Greek into the vernacular Syriac of that time.
[2] A. Oepke (1964–). ἀπόλλυμι, ἀπώλεια, Ἀπολλύων. G. Kittel, G. W. Bromiley, & G. Friedrich (Eds.), Theological Dictionary of the New Testament (electronic ed., Vol. 1, p. 397). Grand Rapids, MI: Eerdmans.
[3] B. Otzen (1977). אָבַד. G. J. Botterweck & H. Ringgren (Eds.), J. T. Willis (Translated), Theological Dictionary of the Old Testament (Revised Edition, Vol. 1, pp. 20–23). Grand Rapids, MI; Cambridge, U.K.: William B. Eerdmans Publishing Company.