Is knowing about wicca's what safe? (An apostrophe with an "s" after a proper noun indicates that the person, place or thing owns whatever noun follows his/her/its name. For example, "Mary's lemons." We know the lemons belong to Mary because of the 's. Other examples: "the school's cafeteria", "my family's home".)
Wicca is a religion. How would learning about any religion harm you and your family?
Magic and fairies however, are not what the religion of Wicca is about. Runes are not Wiccan either.
Some Wiccans work with magic, as well as some Wiccans may use runes, and some may believe in fairies - that doesn't mean these things a part of the religion of Wicca. Just like some Christians cook, and some Christians like cycling, but that doesn't mean the Christian religion is about cooking and cycling.
Runes are the letters in a set of related alphabets, which were used to write various Germanic languages before the adoption of the Latin alphabet. No more or less dangerous or harmful than the alphabet you used to type your question.
Some people use varioius symbols in working magic - they are focus aids. The symbols themselves have no inherent power.
Knowledge itself is not dangerous. What you *choose* to do with what you learn, with the knowledge you have, is up to you. For example, your doctor has knowledge of medicine. Your doctor knows as much about what can hurt you as he does about what can heal you. But your doctor chooses to use his knowledge to heal, not to hurt.
If information scares you to tears and makes you feel like you and your family are somehow in danger, I have to wonder what you're doing using the internet, which is also known as the "information superhighway".