Snake hooks are fairly cheap. Go to Bean Farm or Reptile Basics. Can get a decent one for $20 or so. You probably aren't going to be using a snake hook to actually lift a large boa. You more or less just use them to turn the snakes head or let it know its not dinner time. I tried using mine on my SD retic and it actually made him mad lol. He opened his mouth at it so I quit using it. I just use a twisted up paper towel and rub it on his head when he gets excited about the cage door sliding open and thinks its dinner time.

Your boa is probably scared if its new. It is just being defensive. Give it time to get used to the cage and new smells. Just change its water every couple days. I also sometimes leave one cage door open if I'm in the room and if they want to explore, they poke their head out and then will climb on me. If they don't want to come out, they do nothing when the door is open and sit in the same place or will just have their snoot sitting on the litter dam which seems to mean 'I want to look out but I don't want to come out and explore'.