Can oral contraceptives delay healing after wisdom teeth surgery?

No, but. Oral contraception has not been shown to delay healing of extraction sites however there is an observed increased chance of alveolar osteitis (dry socket) with women using oral contraceptives. Also of significance is that antibiotics prescribed after oral surgery have been shown to inactivate birth control pills so alterative birth control should be used when takeing antibiotics.
Yes. It has been shown that estrogen can delay healing by causing disruption in the normal healing sequence / maturation of the blog clot. It can be quite variable as to what degree it affects healing, however. Females in the early stage of their menstrual cycle and those taking estrogen containing oral contraceptives, have been show to have an increased likelihood of a "dry socket" as well.