Not sure what you're asking - are you saying why did god let satan hang out in heaven for so long after being a dick to Jesus, or are you asking how he was able to be a dick to jesus if he was in heaven?
On the first one - I suppose the answer is the same as why it's taken 6000 years to demonstrate that god's rulership is the only way. Pretty sure that should only take like 2-3 (non-overlapping) generations to be sufficiently proven. I guess JWs would fall back on the 1000 years is as a day to god nonsense.
For the second - the JW doctrine is that until 1914 satan had free reign to travel between heaven and earth, but after he's confined to the earth. So before he'd go up to god and taunt him and stuff and then he'd come down to earth and dick around with people and cause tsunamis and such, then back to heaven, etc.