Older tanks can have this particular algae issue too
For example, if I forget to close my blinds my tank gets a lot of direct and indirect light that really algaes up my glass fast! Algae LOVES that yellow (sun) light! It's a lot worse in the winter when the sun is really low as my front window is south facing. Closing my blinds helps a lot!
Also, 9 hours of halide time seems like a pretty long photo period to me! And also, what colour temperature are your halides? Do you have any supplemental lighting like t5s or LEDs?