Re-Entry to USA

My daughter is an Australian citizen currently participating in a Work n Holiday program in Florida through YMCA. Her visa in her passport was stamped for 4 months (expire March 09), but her DS20-19 is for 12 months (expire end November 09). At the end of November 09 (eg within her 30 day grace period) she is planning a cruise from Miami to the Carribean. This will mean re-entry into the USA and from what I have read, the 30 day grace period is only good if she stays within USA and doesn't leave and try to re-enter.
My question is this: Can she apply under the Visa Waiver Program to enable her to re-enter Miami after the cruise? If so, can she apply for this on-line now, whilst her working visa is still current? She would really like to apply now and obtain approval rather than leave it too late, but we are worried that because she is currently in the system under the working visa, it may reject her visa waiver application.
I would be most grateful for any information you can provide. I have also made enquiries with the USA Consulate in Melbourne, Australia (where my daughter obtained her visa), but haven't had a reply to date.
Thank you so much for your help!

Visa waiver doesn't involve getting a visa - it's a program under which the need for a visa is waived. If she wishes, she can apply for a tourist visa - but it would be a standard visa application.

Thank you for your reply. I take it that she is not eligible to have the visa requirement waived (although she is coming back in as a tourist - but only for 3 weeks eg the remainder of her original grace period) due to the fact she has been on a working visa. That is what the consulate have indicated. I have just been to USA and received the visa waiver as I was only there as a tourist.