New kitten

I'm going to adopt s little orphan kitten, he's 6 weeks old. My sister is a vet tech and has been bottle feeding him.
I had him for the weekend to see how he'd do.
I really love him but am worried about leaving him while I go to work.
I live in a small apartment and he had the run of the house except for night time which I put him in a tent I set up in my living room. It's s 2 person tent and quite roomy. I put his little carrier, cat bed, litter and food/water. He slept all night,
So can I put him in there while at work or leave him loose? I have another cat who is just hissing at him but seems interested in the kitten.
Any advice for my work situation?

Better to leave him in the tent while you are at work (it doesn't get too hot in there does it?). Kittens this small can get trapped or stuck in places and suffocate. Try to let him out for time with you before you go to work, and for a few hours in the evening. Once he and your cat get friendly, and he gets bigger and more used to your place, you can allow him out during the day. It's just too risky right now.