Apparently, Samsung Display will commence the shipment of the S9's OLED panels as soon as this November, which is two months earlier than usual, feeding the notion that the next Samsung flagship might be released before the usual April/March timeframe.
The source adds that it's usually the displays that ship first to the assembly lines, then the rest of the components get together, and form the final retail product two or three months after the first panels hit the conveyor belts. Since the Galaxy S8 displays started shipping in January, and it got announced the end of March, the insiders rightfully deduce that the S9 might be unveiled earlier than usual - at the end of January, with shipments beginning mid-February.
It is not that far-fetched of an idea, too - given the rumors that the S9 and S9+ will ship with the same 5.77" and 6.22" screen panels of their predecessors, and the Infinity Display design, the only thing Samsung needs to upgrade are the processing power and slap the dual camera set from the Note 8.
As for why would Samsung try to pull the S9 forward, well, the industry insiders cite the eventual launch of the iPhone 8 as the main reason for the early birth strategy, trying to defend its sales against what may turn out to be a hit among smartphone buyers. Given the rumored iPhone 8 start price, they might not upgrade for the next two years at least, so the S9 would be airdropped earlier to try and mitigate the eventual iPhone 8 success.