And there's no reason to believe it will drop an extra $11 tomorrow.
There's no reason it will drop at all.
Since the $8 being disbursed from the company treasury does not translate directly to $8/$108.95 in the valuation of the company, it's not even particularly likely that the price should be $8 lower at open. This is unnneded cash, and giving it to shareholders won't have a material effect on the future value of the company. But most people don't think past the simplest combination of mathematical symbols when doing valuation of stocks, so "$108.95 - $8" is as far as they go. And it's irrationalities like that that make a market worth speculating in.
There's probably a few bucks to be made just buying at whatever price the suckers are asking for in the premarket, because they'll likely be doing the math that way and undervaluing the company until the real volume starts and the equilibrium of market forces finds the balance.