You can use ought in the present tense to say that someone probably has something.
Definition of ought:
Used to indicate a desirable or expected state.
e.g., He ought to be able to take the initiative.
But you cannot use the phrase ought have with the present or future tense.
Definition of the idiom, ought to have (done something):
Used when you realize that someone did not do the right thing in the past.
e.g., You ought to have listened to the warnings.
e.g., I know I ought not to have taken the money.
So, your example sentence is confusing. If you are using "ought have" idiomatically, the sentence does not make sense, because it means:
I regret not to have time tomorrow to meet you.
But, if you are using "ought have" in the literal sense, it does make sense:
I will probably have time tomorrow to meet you.
To avoid confusion, I would phrase the sentence in other words, like you wrote:
I should have time tomorrow to meet you.
In general, try to avoid using idioms in the literal sense (even if it is obvious based on context that you do not mean the idiom), because people may not understand that you are not using the idiom.