I recently came across VBA code in Excel that used this command (Application.wait) to delay until the program fetched the data from an ODBC source for use in a pivot table. In order for such a thing to be necessary, retrieving data from odbc must be async. Is that true or the Application.wait is useless?
According to Microsoft's manual the Wait method suspends all Microsoft Excel activity and may prevent you from performing other operations on your computer while Wait is in effect. However, background processes such as printing and recalculation continue. (emphasis mine)
As you can set an ODBC Connection as a background process (ODBCConnection.BackgroundQuery property, set it to True) so, yes, it can run async.