I noticed that Quad 9 is not able to respond to the spy.pet query:

$ dig spy.pet @9.9.9.9 +short
;; communications error to 9.9.9.9#53: timed out

But Cloudflare DNS is able to do it:

$ dig spy.pet @1.1.1.1 +short
104.26.0.165
104.26.1.165
172.67.74.73

And to be sure, I checked another domain with the same TLD to rule out the option that Quad9 is unable to handle the .pet TLD, but I received a correct answer…

$ dig hello.pet @9.9.9.9 +short
3.64.163.50

Does Quad9 censor DNS queries?