Nine years? That means you’ve been having these experiences since you were only 5 years old. It is not uncommon for non-psychotic children to have hallucinations. However, the fact that they have continued for so many years and that these hallucinations interfere with normal functioning suggests that they are not the product of an active imagination. I do understand why you are upset and why you want answers.
Parents generally don’t want to believe that a child might have a mental illness. Sometimes pediatricians don’t recognize it either. I can’t make a diagnosis on the basis of a letter, but I can tell you that the experiences you describe should be evaluated by a mental health professional to determine whether or not you need treatment. Talk to your mother about seeing a professional — if only for your (and her) peace of mind.
I wish you well.