Thank you for contacting Syncfusion Support.
We analyzed your query and you can put the vertical scroll bar on the left side of the GridDataControl instead of the right side by customizing ScrollViewer ControlTemplate and set that customized ControlTemplate to customized GridDataControl style. We have prepared a sample based on your requirement and attached in the following location for your reference. We have attached the sample in both GridDataControl and SfDataGrid controls:
GDC Sample location: http://www.syncfusion.com/downloads/support/forum/118910/VerticalScroll-1021799962.zip
SfDataGrid Sample location: http://www.syncfusion.com/downloads/support/forum/118910/VerticalScrollBar-1124258424.zip
Please let us know if you require further assistance.