Red 6 held back in trade centre as 9 is in catalogue (7-8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Reversal of ( … held back ) SIX(6) contained in ( in ) MART(trade centre/market) + reversal of ( as … is /is held back like 6 in the first half of the clue) NINE(9) contained in ( in ) LIST(a catalogue/a register of items).