Let me get this straight. You're with this guy for 9 years, you get pregnant and he leaves the state. Within a year, he's already been married 5 months to a JW, yet he's not baptised.
Something about this smells. Any good JW girl wouldn't have married a guy who's just studying and not baptised. And even to get married so soon seems suspicious even if the JWs weren't even involved. How long could they have known each other? He knew he had a child on the way.
So this guy you've been with for 9 years leaves you on your own while pregnant, marries another girl, and you want him back??? Forget about whether he's becoming a JW or not, he's a loser. All you need from him is child support. You have no reason to accept this man back. And the fact that he's becoming JW should just re-affirm that decision.