Here is a chain of generic premade cables, using amazon.com ASIN's so you can look at the pictures.  Steve at Sounds Heavenly could make you a single, custom-wired, cable (and custom left/right lengths too), but apparently right now he's up to his ears in work.  I'm not recommending amazon or these specific cables -- you could easily substitute the same pieces anywhere from MonoPrice to AudioQuest!  You need: 

1 of "3.5mm Stereo Mini Jack Male to 2 RCA Male Stereo Audio Cable", ASIN: B017XNCK6I (from TV)

2 of "RCA Female to 2 RCA Male Y-Cable", ASIN: B074Z5C94X (left->2 left, right->2 right; ignore the white & red colors)

2 of "3.5mm Stereo Mini Jack Male to 2 RCA Female Adapter", ASIN: B01ET3Y2SO (combine 2 lefts to one A9, 2 rights to the other A9)

There are other ways to accomplish the same thing, especially because you probably want a few feet extra length to reach from TV to speakers.  But I would accomplish that with male-to-female 3.5mm "headphone extension cord"s.  (P.S.  Don't forget to set the Line-In Delay to zero and turn off multi-room distribution with the B&O App, so audio doesn't lag behind picture.  See /forum/general-discussion-and-questions/semi-solved-beoplay-a9-mark-3---inputs-delay-bluetooth-amp-line-in )