How to create multiple record layout when data merging in Master Pages in InDesign

Do you hae a single page master, or a double-page one? How many pages are in your docuemnt? 
A double-page master or a document that has with more than one page will result in Multiple Record being grayed out. 

Working backwards:

"Can you have multiple updatable data sources for different sections of the document i.e. different date for sections in a brochure for example?"

No. Data Merge is very much a one-off operation in most ways. Even your notion of "updatable" is limited in concept, in that an updated data source doesn't necessarily update a merge document—more like it facilitates a new instance of merge, resulting in a new merge document.

"Does anyone know of a way to create multiple data instead of single pages?"

Yes, to make your 9-up scenario, you'd have to start a new, single-page document and set up the first of the 9 instances at a size that will fit on the page 8 more times.

Then when you choose Create Merged Document, InDesign will identify that there is space on the page for a Multi-Record Layout, and the Multi-Record Layout tab will become available, allowing you to control the margins, columns, and spacing of the 8 additional instances InDesign will automatically generate and polulate with the next 8 records. Additional pages will also be automatically generated, as many as needed to accommodate the number of records in the data source.