First, check if it is blocked. You want to use it for a valid work purpose, so it should not cause a real problem with your boss even if it hits the filter. So it should not be risky to check it.
Next, if it is blocked then talk to your boss about getting IT to unblock it for the developers. Most places, IT will not unblock things for you but need your boss's approval that it is necessary for work.
It is a very useful tool to have in your pocket. Likely if it is blocked it was because someone was spending too much time on it. So if you get it unblocked be very sure not to spend all day on it.
If your boss needs convincing, show him something you want to find an answer to and then show him the answer on your phone, so he can see for himself how useful it is. It would be weird to have a boss who is not already aware of this, but if it happens it is most likely in a place where the site is blocked.
As an aside, using it can be a bet different in the corporate world. It is better to use it as a guideline rather than blindly copying and pasting as many students do. If you think something will solve your problem, but don't understand what they did then ask further questions or dig into the books or other Internet sources such as the technical manuals for the software you are using until you understand. You want to get better for having used it not just keep having to ask or look up the same questions over and over. You are going to have to support that code over time, so you need to make sure you understand it.
If you can't find your answer and have to ask a question, then make sure you give enough detail for the potential answers to understand the issue, but disguise things so that there are no corporate confidential pieces of information (actual URLs, database table names, etc.) being given out. And don't ask someone to just code your answer, your company isn't paying us they are paying you.