The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
You can check this link to the Tensura Wiki (Look at the first paragraph of his background):
https://tensura.fandom.com/wiki/Veldanava
You can also read the light novel in this URL (Read the epilogue and you will find this line: "He understood. Veldanava had given up being ‘omniscient and omnipotent’ by his own free will.")
https://tensurafan.github.io/read/v16
(If there is anything else I need to prove that this character was Omnipotent in this form can you let me know? I don't know how to prove this character was tier 9 since there was nothing until after he gave up his omnipotence but I hope text evidence is enough. I also couldn't make the links URLs so you will have to paste them directly into your search engine)