So let's review the bidding. The definition of a load bearing wall is one that holds up more than its own weight. The load typically comes from joists that bear on the wall, another wall directly above the bearing wall, or framing elements that bear on the wall. There is NO WAY to determine if a wall is load bearing without physically inspecting the space above the wall to determine if any framing elements bear on the wall.
I find it amazing that a registered professional structural engineer would declare a wall to be load bearing without verifying the conditions above the wall. Even if the engineer had stamped, as built plans, he still needed to go into the space above to verify that the house was actually built the way the plans show.
You stated that the engineer was a structural engineer. You did not note if you had a contract with the individual, or whether the engineer was paid for services. If you had a contract, and/or if you paid this person, you have a right to demand that they come back at their own expense to update the report based on actual conditions in the house. No one on an internet chat forum can tell you with certainty whether that wall holds up anything above without looking at the framing, but that is what you presumably paid for, so a call to the engineer would be in order.