Folk lore or actual scientific data through experience?

"A meteorite can contain the power or energy to cause mutations in DNA"

I don't think so, unless it is radioactive, and I never heard of a dangerously radioactive meteorite.

"Meteorites can contain phosphorus which can glow underwater"

Meteorites may well contain trace amounts of phosphorus, but then so do many ordinary rocks. Pure white phosphorus does glow in the dark under some conditions, but a meteorite would not contain pure phosphorus because it is highly flammable and would burn off on entering the earth's atmosphere.

"if a meteorite has phosphorous, then it came from a life bearing world that is long gone"

No, there are many inorganic sources of phosphorus. If it was in a meteorite then it most likely has never been on a planet.

thats not even folk lore. thats comic book science.

meteorites dont have any magic mutation power. if you are too close to the impact the blast will kill (not mutate) you.

white phosphorus does glow but it is highly flammable and would ignite if it was in a meteorite that would hit earth.

the phosphorus in our DNA comes from anorganic phosphorus. it is not produced in our body!

therefore: No this does not mean that this meteorite comes from such a world

I think you are getting confused with red kryptonite!