In addition to the massive amount of evidence we have proving that the verses 9:128 and 9:129 are not part of the original Quran via the mathematical structure of the Quran, the historical account also confirms this fact.
This Sura is considered Medinan except for these two last two verses which are considered Meccan. This is the only Sura which such a phenomenon is claimed. Some claim a similar phenomenon in sura 12, but not accepted by most scholars.
While every other verse had numerous witnesses and parchments validating their authenticity these two verses were the only verses that relied on a single parchment and was validated by only a single companion of the prophet, Khuzeimah Ibn Thaabet Al-Ansaary.
The reason it was still accepted as part of the Quran despite not meeting the criteria set forth for all other verses was because someone claimed a hadith stating that “the testimony of Khuzeimah equals the testimony of two men.”
Also, it is the only verse where two of the attributes of God “رَءُوفٌ رَحِيمٌ / kind, merciful” are used to describe the prophet.
Below are the Hadith that show the historical account of how these verses were decided to be included in the Quran despite the numerous issues regarding witnesses and testimony. It is note worthy, that these are considered the last verses of the chronological revelation of the Quran with the exception of Sura 110 which is only three verses.