No, no, no, and no. and some more no.
Bettas reach sexual maturity at 3 months, and this is also their sexual peak. After 7 months of age, its very hard to breed a betta.
They oh so inconveniently develop their full finnage at 8 months. Ever notice how pet store bettas have big fins? Cause their old.
And asking how to make a betta grow is like asking how to make a human grow. Well, how do you do it? The fact is, time will grow things, theres no magic pill that will make your betta huge. And why would you want a huge betta? There are serious health risks when betta's fins get to large, which are extremely noticeable in halfmoon males when the weight of their fins is simply to great for them to swim to the surface for air. or swim at all.
So count your blessings. your going to have a good friend for a long time :)>