If I attach a Grass energy from my hand using M Sceptile EX's "Jagged Saber" attack to a benched Malamar EX, will I be able to use Malamar EX's "Hyper Hypnosis" Ability to put my opponent's Active Pokemon to sleep?
Yes, you can. An Energy is being attached from your hand to Malamar-EX, so Hyper Hypnosis can be used.
Source: TPCi Rules Team (2015-10-29)

Relevant cards

Note: All applicable cards may not be listed below.
XY4_115
XY4_58
XY7_8
XY7_85