Krishna attended the Swayamvar alongwith a big contingent of Yadavas without any intention of marrying Draupadi either by him or by any of his contingent. They were all told not to take part.
Krishna had already heard that Pandavas were not burnt in house of lax and are alive. He was aware that Pandavas will be arriving to Swayamvara as directed by Veda Vyasa and probably in disguise. His agenda was , if any, to assist them in case of necessity. However, no such help was necessary and hence he silently watched the fight post target breaking , though Balarama asked if they should intervene.
He would not have specifically planned anything, he need not have to, his being there itself is a substitute for any planning. He can decide then and there anything that is required.
He did not fall in love with her to marry her. He knew she was destined to marry Pandavas and he had no issue with that.
