I just replaced the rear sprocket on my CT1 and noticed that when tightened down there's still a little bit of play if I wiggle it back and forth. Is that okay or should I replace the rubber clutch hub?

If it's "wobbly" play, rubbers won't fix that. It's kind of normal.

If it's back-forth play like sprocket can rotate a lot, then maybe rubbers are needed. Not too common for them to wear out though.

Thank you Mark. I think I'm probably fine.

First bike (CT-2) I ever did, I thought the circlip was worn thin. I bought a new circlip, and the whole thing was the same way. I think I remember from long ago someone suggesting that it was a bit loose to allow for "self-aligning" of the sprocket with the chain and front sprocket in the event the wheel is a little out of true, so your teeth always are aligning with the chain without excess wear on the sides of the teeth. Can't remember who it was who posted that on the old site, but I think that's what was said.
Recently I bought an AT-1E that I am working through. In addition to the front wheel being mounted backwards, and the head being mounted backwards, that rubber damper was glued in with some sort of silicone crap that was monstrous to get out of the female hub portions...once I got the destroyed rubber damper out of there. Got a new one off ebay, along with new sprockets and chain. Back to normal.