I am also considering Ibiza in Sept. Although my plans are not definite yet. If I do go, I will be non-reving to Barcelona on my airline I am employed with from the states. Then non-reving on Iberia which offers 4 or 5 flights daily from Barcelona and they offer 1 non-stop from Madrid. Air-Europa also offer flights from Barcelona/Madrid but I am not familiar with that airline.

Does anybody know a decent hotel or what the the weather will be like for September? Is it still the tourist season for Ibiza? I have looked at photos of Ibiza and it reminds of Cancun.