I echo the wait and see advice, Sprocket was a full two yrs old when he came to us, OK a little old to be neutered, but still, wasn't done growing, a late bloomer, I liken it to a teenager becoming an adult. Yea they are an "adult" mostly but will get stronger and develop with a little more time. I asked my vet if the waiting had hurt Sprocket, she said no, cause his hormones probably made his bones stronger,
I don't know about these things, but I have a jumper and it kind of eases my mind. So unless you have a real need, I'd wait. Just my 2 cents. Good luck either way.