The index is covering, so one seek operation to the start of the range and a partial scan is all that's necessary.

It's not traversing the index 9.5 million times. If it was, the logical reads would be ~27 million. It's traversing the index tree once, reaching the start of the range of rows that match then reading along the index leaf level until it's got all the rows. It's more efficient than a scan as it doesn't have to read the (few) rows that don't match.

p.s. Please post new questions in a new thread in future. Thanks