By putting TRUE in quotes, you are returning a text value. You can return a proper TRUE or FALSE value like this:

=OR(A9="A*", A9="A", A9 ="B", A9="C3", A9="C2", A9="C1", A9="Distinction*", A9="Distinction", A9="Merit", A9="Pass" )

One drawback in putting the criteria explicitly within the formula is that if the grade descriptions change then you have to amend the formula and then copy it again, whereas if you use a table you only need to amend the table.

Pete