The breeder must be a friend then? I haven't heard of any breeder selling animals after only one month. They usually hold them until at least a handful of meals and a shed to make sure everything is working as intended. Whatever works for you I guess. Just know that boas are very easy to overfeed and the damage done wont be seen on the outside until the inside is already damaged as they gain the fat on the organs first and then the body. We have never even seen pics of this boa.
You note that you have identification papers for him yet you call him a red tail and said he *might* be a BCIxBCC cross and say 80% BCI. Don't understand this part since it seems you know the breeder and unless he is just throwing mutts together and wholesaling the babies, he would know what he had and not sure how it's 80% BCI unless you know the percentages of the parents. But anyways, good luck and I'm sticking by my statement that a 3.6' boa is either about 1.5-2 years old or it has been overfed in the sense it has been given too big of meals too often. Good luck with the snake.