Is a header needed for this load bearing wall?
You absolutely need a header. From what I see there, doubled 2x10s should do.
The wall was apparently built like that because 12' studs were expensive or unavailable, so they  built a standard-height wall and then extended it. That probably wouldn't fly with modern code due to the effective hinge point in the load transfer path.
None of that changes the fact that you need to support the framing above the opening as normal. In your situation I'd lay the header in above the existing double plates, then fill down below them to your opening height. This approach retains the lateral integrity of the wall as much as possible.
           |  |            |  |             |  |&lt;-- pin studs (existing, shortened)
    _______|__|____________|__|_____________|__|__________
   |                                                      | 
   |                header                                | 
___|______________________________________________________|__
_____________________________________________________________ &lt;-- double plate
_____________________________________________________________ &lt;-- top plate
    |  |  |________________________________________|  |  |
    |  |  |           ^-- filler block             |  |  |
    |  |  |                                        |  |  | &lt;-- king stud
    |  |  | &lt;-- trimmer studs -------------------&gt; |  |  |

Be sure to temporarily support the framing above. There are a few good posts on that here if you need advice.