Possible Clues:

• Rounds
• Courses, or parts thereof
• Of course they're round
• Where they're going around with the alternative pieces
• The alternative to pieces, as a matter of course
• 9 across has one of them - or pieces of them
• One goes around in them, or perhaps not wholly so
• Paths of planets
• One gets around them, or parts of them (6)
• Courses or parts thereof