That canonization carries infallible papal authority is not clear. A few theologians have asserted it does, but the Church has never ruled one way or the other.
Padre Pio would not be a saint if the Church had not ruled on it.
There are three steps to sainthood
1 Venerable
2. Blessed (one miracle proven)
3. Saint (at least two miracles proven)
Read Ruffin’s book that An American Mother previously posted about. It is chock full of Padre Pio miracles.