User blog comment:Aizen.sama/Are Espadas, Vasto Lorde(s)?/@comment-1861226-20100421011125

Yes the Espada, with the exception of number 9, are to be considered Vasto Lordes. Number 9 states that he is the only Gillian. This already confirms the rest are of higher rank (although that means the rest could be Vasto Lordes or Adjuchas). However, Aizen does quote when talking to Ichimaru that his plans are to gather the Vasto Lordes. This can be presumed that he already gathered them to create the Espada.