4chan has a post number next to every post. It's like a gamble where people try to get repeating digits or certain numbers to "Confirm" what will happen.

Posts have an incremental id attached to them. He says that if his post id ends with 9000 trump will be president. His id ended in 9000

Right there with ya.

4CHAN lingo. sequential numbers = meme magic. Dude just predicted his random generated numbers and then all of the replies were full of 777's and other sequential numbers (all randomly generated). Chaos God Kek the Frog is blessing the post.

The same number several times in a row is good luck on the chans.