who tried to kill Bran?

[Hippocras]

^nor was he in KL when Joffrey died. when he wants to cause trouble he makes sure he is far away from where that trouble is.

Which means of course that his plans are more vague suggestions and general guidelines than specific directives. He did not tell Joff to hire a killer to murder Bran. But he did plant rumours and provocateurs in the King's entourage and tell them to make sure things did not go smoothly.