Do the words Sacred, Divine and Spiritual have any context in Buddhism?
I don't think we are (nor should we be) looking at sacredness of the idol but rather Buddha's emanation and nature in our own mind. We can find a Buddha in ourselves. That is at least true in context of Mahayana and Vajrayana (emulating Buddha's mind or Deity's mind). In Pure Land however, this gets very Idol-based so sacredness is stressed, on the other hand it's Amidaba Buddha, not Shakyamuni. Zen has tendencies to do the opposite, the story of "cutting off Buddha's head" or famous "kill the Buddha" koan are some examples of desacralisation. With Theravada I do not know but I have seen Thai Theravadins in a temple taking Buddha's sacredness as an idol quite literally, praying and chanting to statue as if to the divine being - at least that was my impression.

Personally, I gravitate towards seeing Buddha as an object of my true self using a specific practise (like certain Sadhana), thus I completely negate sacredness, divinity and refrain from idolising the Buddha in any way. I consider such divine elevation a hinderance and obscuration to be removed in order to realise Selflessness of things and achieve meaningful progress on the path.

Everyone is divine and therefore no one is divine - everyone is the Buddha, we just have to see this capacity.