It doesn't sound like a ton. If you said 8 or 9 times a day? Okay, ya, that's a bit much. If you want to stop, then just stop. Masturbation is normal. For some guys, it does impede their normal sex life if they have trouble having sex with their girlfriend or boyfriend. Masturbation is really direction self applied manipulation and actual sex can feel a little bit different. Or if you just don't want to get caught up in it and it causes you anxiety, then you can distract yourself. If you get the urge, do something different. You could go for a run/walk, take a shower, text a friend, snap chat with a friend, read, play a video game, etc. Just have some go to activities to do when you get the urge and the urge will pass. Then distract again when you get the next urge.
What kind of negative affects are you having from it?
Generally speaking, masturbation is normal and has some health benefits. If you're masturbating 8-9 times over 2 weeks, that's not even once a day, and shouldn't have any negative effects.
Is there something you're doing with it that you don't like, perhaps watching porn?
Again, generally speaking, a good way to not do something you don't want to do is distraction. Change your routines. If you'd normally masturbate before bed, for example, read a book or play a game on your phone. If you do it in the shower, only allow yourself a few minutes in the shower, and time yourself. Set an alarm on your phone, and get out when the alarm goes off. Reward yourself when you don't do it.
If you watch porn, block the sites on your phone or computer. Google how to do that for your specific browser or phone. If you have porn downloaded, get rid of it.
I'd like to understand why this is so negative for you so I can offer better, more specific advice.