Yes-but they sincerely believed it was a religion. So scary - disconnection as the "acceptable" gas chamber.
As Cruise said: "Imagine a future with no SPs."
No, the higher ups did not, maybe they convinced the young ones but they were merely intent on inventing Tuetonic alternative religion to the "Jew tainted" Christianity.
I've read countless books on the SS and Nazism. The fact is they decided they needed to "invent" a religion to give some historical basis to Nazism. Most Germans were Christians and they didn't want divided loyalties among the ranks. Most high ranking Nazis were atheists - Bormann, Hilters right hand man, hated Christianity and felt it's removal should be a central aim of nazism.
So they came p with a hodgepodge of occultist stuff, old "Teutonic" lore (much of which they just made up as they went along) and a big focus on "blood" which fitted their needs and idelogy quite well. They even financed many "anthropology" expeditions to try and give some credence to the BS about "Aryans" they were making up - unfortunately most findings merely disproved their theories. Real anthropologists and scientists considered the Nazi research a farce. (They were quite keen on proving Aryans were a super-race, which they descended from, and decided it's origins were to be found in Tibet - things didn't really pan out to well. Also far more has been read into this expedition by conspiracists than was really there - it was not some holy Grail search for Aryan roots.)
The occultism or a Aryan religion of the Nazis was merely an invention to help them consolidate power and give it some historical/religious significance. It's been found again and again you cannot remove a religion from a people with out replacing it with something else. I would argue the Nazis didn't try to replace the church with a blood religion, but with a cult of personality around Hitler. Hitler worship as a cult was far more successful than any blood religion.
I would say of all the Nazis in power Himmler and Hess may have been the only true believers - and they were both considered a bit nutty. Goebbels was happy to use the stuff when it could further his propaganda aims. How they fed this stuff to the lower ranks (esp of the SS) to get them to do their bidding and remain loyal, and how much they ranks actually believed in it, is a matter of debate.