I have done this program for 1 week now. my friend have done it too.. we have used to low weights and to many reps but we will adjust it when we get the technique 100%. I think it works well for us. right now I my legs are shoot. Gonna rest until monday.
another thing I like about this program and compound weight training... is that it takes alot less time. I can do this program in 30 min or something like that.. pretty close to 30 min atleast. I used to have a 3 hours program in the old days. No wonder I got feed up with weight training. 3 hours= epic boredom.
Standing push press isn't the same as a strict military press, you use your legs to assist you in getting the weight up (it's still racked at your shoulders but you know what i mean), generally lets me go heavier than i would be able to do on a strict military press, not to mention i just personally like the move better, you may like military press a bit more :)
If you're working your legs to the point where they're exhausted, then as i said, 9 sets is more than sufficient for you right now. Give it some time and see where you end up in say a months time, little longer maybe, then adjust as needed.
Your program is simple short and sweet. But one of the things i see that will eventually become a hindrance to your training is the rep range. Your strength will naturally increase witht the program that you have designed but you will suffer loss in strength endurance due to the low rep range of the exercises. Obviously if your just starting out you can adjust this as you go along.
Also ask your friend to get checked out for his back problems. Lifting heavy will agravate existing injuries he has.
I just hope that you don't go onto the mat in 3 months time thinking you'll be able to wipe the floor with everyone due to your new found strength, only to find that after a couple of exercises your fatigued and moving at 50% power.