So much has to do with the programming of the WODs and accessory lifts. If you find a good box near you with knowledgeable trainers, then yes you can achieve what you want.
MHP has it available on their website right now (mhpxfit.com). Its only been available on their site for a week or two so it might be a couple weeks before bb.com and other supplement retailers have...
If you're looking to put muscle on yes it will help. But very little of the strength gains made would translate into your rugby game. I'd stick to different variations of the squat. They're more...