TheRealDummiz:
Sounds to me like you're not getting enough gs voltage. One way to fix it is having two transistors in series, one powered by 3.3V gs to grant 9V gs to the next. Another way is making a small divider network that will hold the transistor just-under activation voltage, then when signal goes high voltage increases about 3V above the divider network. Google is your friend
Diagnosis is partly correct (except for the part where OP was using a BJT rather than MOSFET transistor), the solution is poor. You don't want to use extra components to switch your MOSFET when simply using a different MOSFET (in this case, one with ower Vgs to switch fully on) can solve the problem.