Intangible assets - Intangible assets other than goodwill (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Finite-Lived Intangible Assets, Net
Accumulated Impairment	$ (44,400)
Accumulated Amortization	(906,785)	$ (636,158)
Intangible asset amortization expense	270,627	2,126	$ 50,377
Intangible Assets, Net (Excluding Goodwill)
Gross Carrying Value	17,136,506	696,506
Accumulated Impairment	(44,400)
Accumulated Amortization	(906,785)	(636,158)
Net Carrying Value	16,185,321	60,348
Customer relationships acquired from the Transaction
Finite-Lived Intangible Assets, Net
Gross Carrying Value	10,740,000
Accumulated Amortization	(268,500)
Total	$ 10,471,500
Estimated weighted average life	10 years
Impairment charges	$ 0
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense
Intangible Assets, Net (Excluding Goodwill)
Accumulated Amortization	$ (268,500)
Licensing and certification rights
Finite-Lived Intangible Assets, Net
Gross Carrying Value	696,506	696,506
Accumulated Impairment	(44,400)
Accumulated Amortization	(638,285)	(636,158)
Total	13,821	60,348
Impairment charges	$ 44,400	$ 0	$ 0
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Intangible Assets, Net (Excluding Goodwill)
Accumulated Impairment	$ (44,400)
Accumulated Amortization	(638,285)	$ (636,158)
Licensing and certification rights
Indefinite-Lived Intangible Assets (Excluding Goodwill)
Gross Carrying Value	5,700,000
Net Carrying Value	$ 5,700,000