Subject test scores *should i indicate that they're planned or no?

I’m planning to take the math level 2 and chem subject tests in December but I’m not sure if I’m going to do well on them. Should I indicate on the UC app that I’m planning to take these subject tests or leave it off as if I’m not going to? Am I allowed to send in the subject test scores through score report after I submit the application after I receive the scores (if they’re good scores) even if the UCs would not be expecting to receive them? I heard that applications with pending December tests get held off to be reviewed sometime in January while they start reviewing applications in mid-December. Thanks in advance!

bump

I believe that the score deadline is December 31 and if you wait for the score results before sending, they may not make the deadline. I think to make the deadline, you need to send them blind. If you feel you will not do well, then why take them in the first place?
It is up to you if you want to put them as planned or not at all.