You do not need a Professional Seller account, or even need an Individual Seller Central account to use SAS!
The only thing to bear in mind is that there are a couple of data points we won't be able to retrieve, (e.g.: eligibility, dangerous goods), without being connected to a Seller Central account; the other 95+% of data is available without a Seller Central account, and having an Individual or Professional Seller account won't make any difference for retrieving this data.
To connect your Seller Central account to SAS, check out our guide here.