They might well be the most intelligent animal on the planet. Ourselves included.
By any measure, their brains -- and their cerebra in particular -- are bigger than ours: raw size, size to non-fat body weight, number of neural connections, several other measures. Just because their intelligence does not include technology means nothing. Cetacean and primate motivations are different.
While we try to imagine what extraterrestrial intelligence might be like, we could start by studying the kinds of alien intelligences we already have here on Earth, from cetaceans to invertebrate nine-brained octopuses (one separate brain in each arm, plus one torus-shaped central brain in their head).