The 35 V rating gives comfortable margin on a 12 V rail (derate to ~21 V as a rule of thumb) and still holds up on a 24 V bus with a 30 % safety factor.
900 mOhm ESR — what it means for ripple and self-heating
ESR is 900 mOhm at 25 °C. On a 100 kHz buck output, the ripple current through this cap generates I² × 0.9 Ω of internal heat — keep the RMS ripple below the datasheet limit to stay within the 125 °C ceiling. The 2917 case (7.30 mm × 4.30 mm footprint, 3.10 mm seated height) dissipates that heat through the board copper; a 2 oz pour under the cap drops the effective thermal resistance.