The tall building is your unit. The higher you live, the higher your status. The fourth floor is a relatively low position, which may be your current position. The floor in front symbolizes people who are higher than you, and your view is blocked by them.
Of course, the ninth floor symbolizes the highest level of the company. Although it's the ninth floor, it feels like more than ten floors, which shows that you are a little afraid of this position.
The only elevator to the ninth floor is a chair without any protective measures, which is crumbling. This is your worry. You are anxious because you don't know if you can go up to the ninth floor. You may not be very confident about this.
Examination is a symbol of assessment here. I don't know what company you are and whether there is an assessment system. Do you have to pass a certain examination if you want to be promoted? It is natural that the paper can't be made. I haven't seen and dreamed about the exam and it went well, because you won't dream about the exam without anxiety, and of course you won't do the exam without anxiety.
You should be more confident now. This dream also tells you that your worry is unnecessary, just like the high number (you have already passed the exam, there is no need to worry about the high number).