This solution might be slow for large volumes of data but does what you need. Any option will be slow because you have seven values in one column and that's against the normalization rules. You're using at least 7 bytes of space when using a 7 bit columns will need less than one byte.
I'm assuming @@DATEFIRST = 7.
SELECT *
FROM (VALUES ('aaaaaaa'),
('SMTWTFS'),
('SaTWaFS'),
('SMaWaFS'),
('aMTWTFa'))x(schedule)
WHERE SUBSTRING(schedule, DATEPART(dw, GETDATE()),1) = LEFT( DATENAME( dw, GETDATE()), 1)