Can I take my immediate upper denture out before eating?? especially if I don't need them to really eat with.

Not recommended. It may take several months before you can adequately eat regular foods. It is very important that you follow the post-operative instructions of your dentist or oral surgeon very carefully. You must wear your new immediate denture at all times, after the surgery, without removing it. This will help to control the swelling and guide the healing of your gums.
Should not. I would listen to your dentist/oral surgeon and follow their instructions. Taking the denture out will not allow you to learn how to use them.
Immediate denture. This usually depends on when the teeth were removed, and how long you have been wearing the denture. In addition to having teeth in your mouth, one of the reasons for wearing an immediate denture is to help the healing process and decrease swelling. Ask your dentist if and when you should remove the denture.
Depends. If all the tissues are completely healed over, then , yes you can. You need to learn to eat with them, even if only a little at a time. Otherwise you will accelerate bone loss and they will fit even looser. See the Dentist or Prosthodontist to evaluate the fit and do a reline if needed. Adjustments are expected, as the tissues heal and shrink. See the doc to help you with this. Good Luck.