What does E mean in 9.0122222900391E-5?

It means $9.0122222900391\times 10^{-5}$. This is known as "scientific notation".

E-5 just means x 10^(-5) i.e. divided by 100000

I have always taken the E or e to mean "exponent of 10." This construction parses in all modern computing languages as an IEEE754 double or single precision number.