Demo: label x-axis in hours:mins
Here's the logic to turn a number into a time eg 9.4 -> "9:24"
If(round(n)==n, n+":00", n-floor(n)==0.6,floor(n)+":36", n-floor(n)==0.2,floor(n)+":12", n-floor(n)==0.8,floor(n)+":48",n-floor(n)==0.4,floor(n)+":24",n+":30")
Look in the file to see how that's used with Sequence() to make a custom axis