Answer: 9 electrons
Explanation: In a neutral atom, it's important to understand that the atomic number or the number of protons that are stored in the core of that element will be the same as the number of electrons in the energy levels orbiting the nucleus.
So if an atom has 9 protons and it's neutral, the atom will have 9 electrons as well since the atomic number is your number of protons and electrons when the atom is neutral meaning it's not an ion.