From both players perspective.

The TAG button opens and the TAG SB 3 bets with the BB folding and the button calling.

The button has AhTs

The SB has Ac9c.

KcKs3c...The SB bets and the button calls.

KcKs3c4h...The SB checks, The button checks.

KcKs3c4h7d...The river goes check check.

Did the SB misplay his hand by checking the turn? If the SB did bet should the Button call again? Should the button call a blank river if the SB did bet the turn and now bets the river?