Genesis 9 and the story of Noah has nothing to do with animals going to heaven. The story of Noah is the third creation account. Genesis 9 uses the same language as Genesis 1-3. The whole topic of consumption of blood - life in the blood, is an allusion to Christ.
Man was not to consume the blood of animals because “the life is in the blood.” Consuming animal blood meant living the life of animal. The consumption of blood was reserved until Christ came and shed his blood for us.
So Jesus said to them, "Truly, truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. (John 6:53:54)
We are to consume the blood of Christ so that we live the life of Christ. God was preparing mankind for its savior.
The story of Noah is also the third creation account in the Bible. God describes the order of creation by telling us what order things were created - man last as the pinnacle of creation. He then allows man to name the beasts and he himself names man, again showing the order of creation. In Genesis 9 God re-orders creation right again by telling Noah what he can eat - he can eat animals because he is (supposed to be) above the animals.
Only the consumption of blood is reserved. Man is not to consume animal blood but is to wait until God becomes man. We consume the blood of God so that we can live the life of God.
What life do you want to live, that of an animal or that of Christ? That’s the question put before the Israelites. They were to wait for the messiah and only then would they be able to consume blood. Some recognized Christ’s words. Some walked away.