You're gonna have to give up more room than what you've pictured for 2 reasons.
First up, 12" high isn't enough for a sub with an 11 3/8" mounting depth. 3/4" bottom panel + 1" gap for pole vent + 11.5 = 13.25 minimum. Double baffle to support a 100lb sub and you're at 14 already.
Second up, that's not enough net volume for a Kicker in any of it's recommended volumes. You have 4.2 after sub displacement. Sealed is 6cuft minimum, ported is 5cuft (weird that it's less than sealed) or 10cuft for SPL or SUV use. General consensus is Kickers like bigger boxes so I'd think at least 8cuft is what you'd need.
Let us know what you want from it, sealed or ported, loud or musical.
My advice, sell it and buy a Sundown Nightshade, IA Warden, SSA Zcon.... so many other choices.... that work in less volume.