The arms US sends to Saudis wind up in the hands of jihadis regardless.
However, I think that the real threat to Putin came from Merkel, not from Obama nor the Saudis. If she just flat-out said that she's willing to cut out Russian Natural Gas and instead have Germans pay an arm and a leg for imported natural gas, there isn't much Putin can do about it. While Russia is a big oil exporter, gas is its most significant export in terms of market share.
Well, where’s Germany going to import from?
There’d have to be at least agreement by the U.S. to ramp up our production / exports as fast as possible, and even then, the next few winters could be dicey, as the above would take time, and Putin could try to force the Euro’s to sign long term contracts.