Note 1 - Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Net income	$ 11,760,896	$ 11,299,282
Weighted-average common shares (in shares)	10,152,909	9,922,701
Options to purchase common stock (in shares)	3,571	4,456
Diluted average common shares (in shares)	10,156,480	9,927,157
Basic (in dollars per share)	$ 1.16	$ 1.14
Diluted (in dollars per share)	$ 1.16	$ 1.14