Disney is in a new environment, with new smells, sounds, people AND another kitten. He's missing him mom and siblings, and this may take a few days for him to "come around".
Meantime, put Destin on the floor and pick up Disney. If he scratches or hisses, that's okay. He's scared.....but if you'll spend a little one-on-one time with him, he'll calm down. It just takes a little patience and time......after all, it's only been ONE DAY!!
Get an old heavy ( athletic ) sock and tie it in a knot. Give one end to Destin and the other to Disney. Let them play tug-of-war with it....or, put a PAPER grocery sack on the floor and let them play hide & seek.
When I had kittens, I made them a "tunnel" to play through. I cut off both ends of some 2 liter bottles and taped them together ( inside & out, so no sharp edges ), and my kittens loved chasing each other through the tunnel. Sometimes, they'd sleep in it. It was clear, so I got a kick out of watching them. Toss a ball for them to chase and "the race is on".
My kittens loved their tunnel so much, that when they outgrew it, I got a "pipe" ( heavy cardboard concrete "piling" form ) from Home Depot, covered it with scrap carpet, and made them an new, larger tunnel / scratching "object". I made a "holder"...... I_I.....for each end, to keep the "pipe" from rolling. My cats ( 4-15 ) STILL run, chase, and play through it. Money WELL SPENT !!
Hope this helps..........PATIENCE & interactive play ( with you, too ) and things should be okay in a few days........
Good luck.......ENJOY the "spectacle".......MORE FUN.......