1.) Westside is a great program for any athlete. It would help if you could do the speed drills outside, but you can also do them indoors in a basketball gym if you can get access to that. There are also plenty of drills you can do in the confines of a weight room. Also, remember that you don't need to be doing the speed drills year round.
I'm assuming your season is fall soccer so you can focus on increasing your strength, endurance and power in the weight room over the winter, and then once spring rolls around you can work on your footspeed outside. Then about 6 weeks before camp you can really work on building up your conditioning or preparing for any tests your coaches will put you through.
2.) It all depends on your metabolism. I'm an 18-y/o collegiate athlete with a very fast metabolism. I eat healthily, but I have to practically stuff my face to keep up. CT's article on Carb-Cycling is a pretty interesting concept. Basically, you eat more carbs (and thus more calories) on training days than on non-training days. Take a look at it and decide what you think will work best for your body type/training needs.
3.) I wouldn't even consider Grow! to be a supplement, it is more of a food. I would consider a good protein powder to be an essential food for those who can't get enough in their diet. Same thing with Surge. I don't know too much about Creatine as I haven't taken it. There are probably more knowledgeable people on here to talk to about that, but my advice is to get your diet set first before you use creatine so you can analyze the effects it has on you a little better.