The correct option is B would not play
In reported speech, the word order and pronouns will be different from the original speech, because the speaker has changed. Accordingly, the tense will also change, in most cases.
Normally, while reporting the speech, the tense will change to one tense back in time.
The direct speech is in the simple future tense. The verb 'will' will hence, change to its past tense form 'would'. The action is yet to be performed, but as the speech changes, so does the tense.
Option B: 'Would' is the past tense form of 'will' in indirect speech. Hence 'Would not play' is the correct form and B is right.
Option A: 'Will' must be changed to past tense as the speech is reported. Hence A is incorrect.
Option C: The modal verb 'should' will change the meaning of the sentence (by indicating an obligation). Hence C is incorrect.
Option D: 'Did not play' is in the simple past tense. It indicates that the action has already been performed. But, the action "will not play) is yet to be performed (rather, not be performed). Hence D is incorrect.