is variablize or variabilize a word?

Solution 1:

Variablize implies to make something into a variable, but only makes immediate sense to software programmers. Since it is not a dictionary word, it must be relegated to a protologism.

That being said, the closest word to your intended meaning is dynamize:

1: to make (a drug) effective (as by comminution or dilution)

2: to make dynamic: endow with force

It is the second definition -- to make dynamic -- that most readily applies here. If you make something static (i.e. a data point) into something dynamic (i.e. a variable) you dynamize it.

Of course, no one really uses dynamize in casual conversation either, even though it is in the dictionary. Don't let that stop you from trying to make variablize into a neologism, though.

Solution 2:

Depending on the context (computer science, data science), I'd use the word "parameterize".