For convenience and better visibility from the community, I am sharing the answer in your support ticket.
The client-side rebind() method is used only when WebService binding is used. When the SQL DataSource is used to bind the Scheduler, a postback is required.
That is why I would recommend using the server SelectionChanged event where you can call the .Rebind() server method of the RadScheduler.
For convenience, I have attached a sample project implementing the suggested approach.
sender, Telerik.Web.UI.Calendar.SelectedDatesEventArgs e)
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