Technically the subscription is per individual user per month meaning that if you need multiple people to use the system, you need an account for each person. If both you and your VA are using the system at the same time, the system might not operate correctly (specifically in the Sales Playbook area and the sales message setting). Also, if both you and the VA are logging details in the CRM and sending out emails, all of that can only be done with one username and info.
But all of that being said, if you are creating your account and the VA is going to primarily be using the system for you, you can certainly share your credentials to them and let them use your account. And if you log in periodically to make changes or look at something that should not be a problem.
We have many customers that create a Pro account and create their sales message and scripts and then give their account to their salesperson or assistant.