It does feel like each player and each team was given a base set of estimated stats (cs, kills, deaths, barons, first bloods, etc.), and then their opponents perform a function on those stats with estimated modifiers (eg: TSM is estimated to give up x number of towers per game, and x number of deaths, etc.) and based on whether those estimated modifiers are higher or lower than the average across all teams, each player and team has their estimated points go up or down depending on who their opponents are for that week.
At least, that's how I generating my own estimations, using formulas on data from their Stats page.
C9 players have a low value because they are at risk of being subbed, even though some of them appear to be in more secure positions than others.
But they can't even find someone to maintain pinned discussions on this board, so I don't hold much hope for weekly updates to estimated points.