Yes! Aluminium in acidic solution is being oxidized to its +3 (Al³⁺) state.
Lets take example:
Make a solution of Sulfuric Acid (H₂SO₄) and add a piece of Aluminium metal in it.
2Al₍s₎ + 3H₂SO₄₍aq₎ → 2Al³⁺₍aq₎ + 2SO4²⁻₍aq₎ + 3H₂₍g₎
In this reaction the Oxidation state of Aluminium has changed from zero to =3, means it has lost three electrons and has got oxidized.
