The ±20% tolerance is standard for tantalum electrolytics — the actual capacitance at 0 V bias will be near the nominal, but under DC bias the capacitance drops by roughly 10–15%, so the effective value at 12 V is closer to 8.5–9 µF.
For a 100 kHz buck converter output, the ripple current through this capacitor will be limited by the ESR — the I²R heating adds to the ambient temperature. At the cold end, ESR rises; at 125°C, the leakage current increases, but the part remains functional within its ratings.
There is no imminent end-of-life notice, so you can commit the BOM line without scheduling a last-time-buy. The molded case (size code C, 6.00 mm x 3.20 mm footprint) is a standard surface-mount package that fits a 2312 / 6032 Metric land pattern — no special pad geometry required.