Could the physical universe have evolved differently?

It depends on what you mean by "the physical universe". Theoretical physics has many different theories with many different universes so in that sense yes it is possible for the physical universe to evolve differently. Our present universe on it's smallest scale (quantum scale) those laws have been set since the big bang; however, on the larger scale random events can and have changed the evolution of our planet. Just one example is the formation of our moon. There are many, many more examples.