He was generally a 2nd striker in Spurs youth and whilst on loan at Orient and Millwall but when his Leicester loan went wrong (he sat on their bench with James Vardy as the Leicester manager preferred another striker so Kane and Vardy didn't play) Kane returned to Spurs for a good 6 months and trained - I think Les Ferdinand was an u21 coach at the time and I suspect helped him change to being a striker, something made possible because he had physically developed his body at that time too.
So he suddenly transformed into being a main striker, and whilst AVB didn't give him too many chances, Sherwood started him in the last 7 PL matches he was Spurs manager, Kane scored 3 goals ...... so Poch inherited a striker who had shown he could score PL goals ...... and he went on from there.