No you can not break 9. It's not the lack of ability. It's life. Running is soon to be secondary to life's real important goals- education, career, women, relationships. Few persist. Experience says you will not have the fortitude to make your dreams a reality. Welcome to the boards
The fact of the matter is that your current pr's don't show that you are capable of running sub 9 without taking some risks. I'm not saying you need to jump off a cliff and run 100 miles a week but you are going to need to go up and if you have 23 weeks that is plenty to hit 70. Just take it 4 miles per week.
Do you do morning runs? Start now. Just inserting 3-4 morning runs of 15-20 minutes is a huge difference for most runners once they get to college (where a majority of sub 9 happens, besides professional obviously). This will make the increase in mileage not feel so bad. And no it's not junk mileage, just waking the body up and getting in a good rhythm in the mornings is good.
As far as specific workload, I would suggest strongly not to focus on any speed for as long as you can. Do you have indoors? If you do and its not a big deal to your school then I would suggest using it as nothing more than training and a little sharpening. You don't need to be doing anything faster than 3200 race pace until 8 weeks out. Then the speed comes.
In a 14 day training cycle I would suggest something like this: Monday- 3 mile morning run, 7 miles at 6:25-35.
Tuesday- Warm up 10 minutes, 1 mile at 5:55 (to get your body ready) 5-7 mile Lt (Tempo, whatever you want to call it) at 5:30-35 pace. If you feel good, notch it down just a bit but don't go crazy. At the same time, if you just don't have it, don't feel afraid to back off and run shorter, but try and keep the pace. 10 minute cool down.
Wednesday- 7 miles at whatever the hell pace you want. And that doesn't mean fast, it means nice and relaxed. As long as your first 4 miles are easy, its okay to feel good and get into a working pace the last 3.
Thursday- 9-10 miles at a working pace, similar to Monday. This is a very important day in that it gives you aerobic strength without being a long run. Think of it as a mid-week long run.
Friday- 2 miles in the morning. 10 minute warmup. 3x3200 at 10K pace. Use your 5k to determine. I would guess somewhere around 32:20 or so which means 10:25. Take 5 minutes between the sets. 10 minute cool down.
Saturday- 8 miles like Wednesday. Your body has worked hard and needs the rest.
Sunday- 13-14 mile long run. This should start off pretty pedestrian around 6:50-7 flat but don't be afraid to get working down to 6:25 for a majority of the run. And if you feel good there isn't anything wrong with pushing 6:10.
Do I think this model can get you to 9 flat? Absolutely. Do I think you are going to have to work your bawls off? You bet. There are very few things at your stage of life though that are as satisfying as flying around the track and knowing that nothing will be able to stop you from hitting the time you want.
I wish you the best of luck, whether or not you follow this training plan.
P.S. This is the kind of training you need to be doing 18-9 weeks out. Don't let up kid. You only have the chance to do this once, don't ever let up.
That Friday interval is not helpful to have him peak for sub 9... I would reccommended a fartlek or progression run of a sort instead... Other than that, go run!!!