Do you think Zelensky will be killed?

can't say if he will or won't. But it's a possibility as russia has shown it can launch weapons deep across ukraine.
I doubt his government's exact location 24/7 is public knowledge, but it wouldn't surprise me if russia takes a shot at him when given the opportunity.
If captured it's possible he may be executed but also very likely he will receive a public sham hearing and sentenced to life in prison. Perhaps used as a bargaining chip if the rest of ukraine keeps fighting.

There are a lot of ways this whole situation can go down and we can only speculate on the likely possibilities and then see what happens.