I got my belly button pierced on friday. Is it okay if I use ivory liquid hand soap to clean it?

Yes. Lever 2000 is antibacterial and may be a better choice to decrease bacteria and decrease the chance of an infection.
Body piercing clean. Cleansing of the area can be done with sterile saline initially. Some antibacterial soaps are irritating so be careful. Any new redness with pain and swelling should be addressed by a physician.