note that if you have multiple databases, with different data tables in each, then you have no way of enforcing relationships between the tables.
If there is a single table (among the 9Gb of data) even approaching 2Gb in size, (say >1.5Gb) then I would be inclined to stop trying with Access and accept you need a different back end.
Note, that I am sure you will also run into trouble if your queries need to extract so much data that they would exceed 2Gb.