Finally found solution.
Dim JoinResult1 = _
(From o In dtcleared.AsEnumerable _
Join a In dtNew.AsEnumerable _
On a.Field(Of String)("Item") Equals o.Field(Of String)("Item") _
Select New With _
{ _
Key .Item = a.Field(Of String)("Item"), _
Key .Bin = a.Field(Of String)("Bin"), _
Key .Size = a.Field(Of String)("Size"), _
Key .Description = a.Field(Of String)("Description"), _
Key .MoveQty = a.Field(Of String)("Move Qty"), _
Key .Action = o.Field(Of String)("Action")
}).ToList()
I just added ToList() at the end. That's it. Now the results are showing up.