"One year of growth equals two years of coaching."
You're in high school. As long as you stay healthy and consistent, the kind of training you've been doing will probably get you under 10:00 just by natural progression.
So how do you stay healthy/consistent? By getting adequate recovery in your training, and by staying under control in your workouts--that's how you avoid getting sick or hurt.
a) Make it a point to go to bed and wake up at roughly the same times every day. That includes weekends! And give yourself a little extra sleep by getting away from the computer or TV about a half-hour earlier than you're used to.
b) One thing (most) high school kids get...is plenty of races. Dual meets during the week, "big" meets on the weekend--you're going to get all the racing you need. So don't race your workouts, too! Don't be too concerned with the specific pace of your tempo runs (especially since tempos, unless you do them on the track, are frequently not measured precisely)--just keep them "comfortably hard." You should finish a tempo feeling like you've built yourself up, not torn yourself down.
Same goes for your track workouts, too. If you happen to have a teammate who wants to challenge you in practices--let him. He can "win" the practices; you win the meets.