JANICE SHEEPSHANKS

I have had my 9 month border collie for 2 months now. I am his 4th home. He was badly injured 5 months ago and had 3 major surgeries on his badly smashed left thigh and was not allowed to go for walks, etc, until 6 weeks ago. My problem is 2 fold. I how do I use up some of his masses of energy as he is not allowed to run or play with other dogs at the moment. He solves brain games in seconds, that could be due to my second problem. 2 - he is a sniffer and his nose is never more than 2cm from the ground. I am trying all the techniques to stop him from pulling and they are not working as his prime objective is to sniff out smells and then mark his territory. Can anyone help? Thank you. Apart from these 2 things, he is adorable.