I’m not getting an objective reward, I sent a driver to work and didn’t get the reward for it,..

You have to do objectives by order, you can't skip one. Example: if your next objective is to buy terminal and after that send driver to work, you first have to buy terminal then send driver to work. If you did it by order but still didnt get reward, maybe its game glitch so try to restart your game and clear cache data. Hope this helps.

You have to wait until the worker has finished their trip.

Only after the driver you have sent to work has finished their route, you get the reward.