Hi arjunrvasisht
By default, the scroll bar should be automatically placed at the top. I suspect there is something overriding this. If you could post a sample maybe we can figure what is causing this.
For now, I can suggest this fix.
Set up a listener on your store
<Listeners>
<Load Delay="1" Fn="scrollGrid" />
</Listeners>
The delay is set to 1 second to ensure that the loading has completed. You can increase it as needed if you want, though I think it should be enough.
And the following JavaScript
var scrollGrid = function (store) {
var scrollHeight = store.count() * 20; //total number of records in the store multiplied by the row height which is 20
App.grid.scrollByDeltaY(-scrollHeight); //scroll negative to scroll upwards
}