Dear Vagabonda, I'm back. Many, many thanks to you!
From Taormina, I took the Interbus to Santa Teresa di Riva. I waited at the bus stop from 9:05 to 10:10. During that time, there was supposed to be two buses to Savoca, and another two buses to other destinations, as stated on the sign. But not a single bus showed up. I asked the lady who owned the negozio if that was the correct bus stop, and kept saying yes. I believe her.
After waiting for more than an hour, I was very disappointed, and told myself that it must be fate that I don't see Savoca.
I went to a caffe to ask for directions to the bus stop to catch a bus back to Taormina. I must have looked very sad. A very kind woman offered to take me up there, saying it's only a few km. I took the offer, since I was so desperate.
So I went to Savoca! Another item checked, off my bucket list.
I didn't dare to trust a Jonica bus to be up there anytime soon. There were two tour buses, and I asked the guide of one of them if I could take a ride with them. The group welcomed me, and commented on how "brave" I was to travel alone. So it ended well.
I want to say that all the other buses from Interbus and AST were very reliable.