Possible Clues:

• Music, say, rubbish? I'm not sure, for jazz pianist
• Jazz pianist's tense time during unfortunate trauma
• Fats Waller contemporary
• Nearly blind jazz great
• 1841 rebellion leader ... also what can fill the square at the crossing of 56-Across and 56-Down
• Great jazz pianist of the mid-20th century
• Jazz musician, the most influential of the swing-style pianists