Cryptozoology is the study of unknown animals. Animals that have been presumed to exist but haven't been seen in ages. Many have begun to think that the animal is extinct or has never existed in the first place. Locals may claim to have seen the animal but there is not enough evidence for big science. Sasquatch is a prime example that everyone is familiar with.
The reason cryptozoology is not a valid science is simply because it is something that is not taken seriously by either science or the general public, in some circles it is openly mocked. The only people doing research in the field are members of the public. These people are well meaning if a bit wacky. The researchers have no idea about the so-called scientific method. To most of them the word science is usually followed by the word fiction. But they do try and try hard. Sometimes I think that they may spend more time holding conferences to congratulate themselves on how great the job is that they are doing. Then they examine the one piece of film of Bigfoot that exists and they do so but they are only preaching to the converted.
The few real scientists who are in the field are often not involved in any sort of field research. They might examine foot castings or the odd photo that may turn up but that's usually about the extent of things.
Most valid sciences have those big schools of learning called universities; there is nothing even close to that in cryptozoology. The best one can do at the university level is to study zoology and then specialize in something closely related to your particular Cryptozoological interest.
How would you develop a curriculum for a subject when no text books exist? What would you study? Bigfoot 101? Or perhaps How to Catch a Loch Ness Monster. No, none of these would work so the idea of moving it to the university level seems absurd.
If more scientists were to start taking cryptozoology seriously it might work as a branch of zoology. For that to happen, science would have to push aside the amateur researchers and put as much stock in them as other branches of zoology do. Science would then need to find funding from somewhere in order to fund all the field work they would need to conduct.
Text books and curricula would still be an issue. Resolving it would be more difficult than you might imagine. Who is qualified to write a Cryptozoological text book anyway? You would need to modify existing zoology books.
Given all the difficulties involved, cryptozoology does not seem destined to become a valid science any time soon.