Hello Bal,
You can, I might have not been clear! 
I think you can retrieve data from SAP Business ByDesign using the standard connectors, SOAP or REST.
I just thought you would use the SOAP web services, so I advised you to be sure to create well maintained Communication Scenario/Arrangement.
If you are using oData, yes there are many services to use in order to extract data from ByD. Even more as you can create your own data sources/reports and so your own oData service. Actually you have one oData per report you have in your system.
So yes, you can query from Boomi using the standard connectors like REST in Boomi. It is just that I personnaly never did it with boomi.
Thank you for your attention.
Best regards.
Jacques-Antoine Ollier