X9SPU-F can fit in SC515-280UB but it’s not optimized chassis, You might need extend the cables for power and fan.
If for X9SPU-F, we'd suggest the below optimized chassis.
SC111T-600UB
SC113TQ-600UB
SC113TQ-R500UB
SC213A-R720UB
SC813T-600UB
SC815TQ-600UB
SC815TQ-R500UB