See my response in your other thread for my advice on how to gain muscle. It follows the K.I.S.S. approach, because all you do is follow the programs as written.
The only possible difference from the written programs would be to put front squats in where back squats are, around 50% of the times. Just alternate weeks. In other words, if you’re supposed to back squat once a week, back squat in week 1 but on week 2 front squat. Or if you are supposed to squat twice a week, same thing. Week 1 back squat both days, week 2 front squat both days. Make especially sure you hit rock bottom with the front squat even if you have to lower the weight. It’s especially easy to only go partway down on the front squat because it feels so weird. Takes time to get used to it.
I think you should back squat, definitely, just not to the exclusion of all else. I’d split it between front squat and back squat about 50/50. I say this because I am unsure of the effects of direct spinal loading at your young age. Some is good and necessary for growth–look at farm kids that work at doing manual labor with heavy stuff. But a crap-ton might not be. I’m wise enough to know that I don’t have the experience to tell you for sure.
–ASK Eric Cressey in his locker room thread about his guidelines for back squatting at your age.
Last–don’t pay any attention to the “weightlifting will stunt your growth” crap. Just so you know, the forces on the joints (including knees, hips, spine, etc) involved in sports, including soccer, baseball, basketball, and football, can be several orders of magnitude greater than weightlifting. If weightlifting were really detrimental to your growth, the forces and torques created by frantically jumping, sliding and tackling would be exponentially more devastating. But no one tells kids to avoid sports because they might stunt growth. Just the opposite. Sports are considered healthy and normal, even necessary.
Note to you, read the “Are You a Beginner?” thread at the top of the Beginner’s forum. Tattoo every word of that on your forehead. Also, in order to become all around well conditioned and built, you need to work your legs very hard, especially your hamstrings. Especially. Like, not just with leg curls. You should also concentrate on your back, in a big way. Being super strong in these areas will give you the supporting musculature to dominate in sports and balance your physique in later years, including helping you bench more and get bigger arms and shoulders. So don’t dig yourself in a hole now by doing only bench, triceps and biceps.
It could take you years to fix your physique if you go training only the muscles you can see facing the mirror. TRUST ME. This is something you will never hear a guy your age saying to you, so I’m going to say it–hot chicks hate a guy with no legs or ass. I literally cannot count the times women friends of mine have laughed at the light bulb “jock” type wannabees with no legs or ass or back. Like, laughed out loud. I dunno that high school girls are the same way, but I guarantee you 100% that college girls notice and laugh to themselves. So don’t dig yourself a hole now.