That requires an arrow. It's possible to beat (9⁹)⁹ using tetration notation and no symbols other than 9. ⁹9 is 9^(9^(9^(9^(9^(9^(9^(9^9))))))), which is rather

That requires an arrow. It's possible to beat (9⁹)⁹ using tetration notation and no symbols other than 9. ⁹9 is 9^(9^(9^(9^(9^(9^(9^(9^9))))))), which is rather larger than (9⁹)⁹. ⁹(⁹9) is just icing on the cake. I'm almost certain the story is a fake.