or these have all been foreshocks to a larger event. Not likely, but who knows for sure....
Not very likely, the 9.0 event released a lot of pent-up energy.
However, it (the 9.0) did have a 7.4(not precise on the size, other than it was greater than 7) foreshock about two to three days prior.
Again, given the energy released (100 x larger than a 7.0), an even larger shock would be considered unlikely.