Intangible assets - Intangible assets other than goodwill (Details) - USD ($)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Finite-Lived Intangible Assets, Net
Gross Carrying Value	$ 29,154,838	$ 17,136,506
Accumulated Impairment	(44,400)	(44,400)
Accumulated Amortization	(2,098,146)	(906,785)
Total	$ 27,012,292	16,185,321
Estimated weighted average life	5 years 9 months 18 days
Intangible asset amortization expense	$ 1,191,361	270,627	$ 2,126
Intangible Assets, Net (Excluding Goodwill)
Accumulated Impairment	(44,400)	(44,400)
Accumulated Amortization	(2,098,146)	(906,785)
Net Carrying Value	27,012,292	16,185,321
Customer relationships
Finite-Lived Intangible Assets, Net
Gross Carrying Value	13,008,332	10,740,000
Accumulated Amortization	(1,459,861)	(268,500)
Total	$ 11,548,471	10,471,500
Estimated weighted average life	10 years
Impairment charges	$ 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
Intangible Assets, Net (Excluding Goodwill)
Accumulated Amortization	$ (1,459,861)	$ (268,500)
Backlog
Finite-Lived Intangible Assets, Net
Gross Carrying Value	6,310,000
Total	$ 6,310,000
Backlog | Minimum
Finite-Lived Intangible Assets, Net
Estimated weighted average life	4 years
Backlog | Maximum
Finite-Lived Intangible Assets, Net
Estimated weighted average life	6 years
Licensing and certification rights
Finite-Lived Intangible Assets, Net
Gross Carrying Value	$ 696,506	696,506
Accumulated Impairment	(44,400)	(44,400)
Accumulated Amortization	(638,285)	(638,285)
Total	13,821	13,821
Impairment charges	0	44,400	$ 0
Intangible Assets, Net (Excluding Goodwill)
Accumulated Impairment	(44,400)	(44,400)
Accumulated Amortization	(638,285)	(638,285)
Licensing and certification rights
Indefinite-Lived Intangible Assets (Excluding Goodwill)
Gross Carrying Value	9,140,000	5,700,000
Net Carrying Value	$ 9,140,000	$ 5,700,000
Finite-Lived Intangible Assets, Net
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
July 2024 Honeywell Asset Acquisition and the September 2024 Honeywell Agreement | Customer relationships
Intangible Assets, Net (Excluding Goodwill)
Intangible assets	$ 1,400,000
July 2024 Honeywell Asset Acquisition and the September 2024 Honeywell Agreement | Licensing and certification rights
Intangible Assets, Net (Excluding Goodwill)
Intangible assets	3,500,000
June 2023 Honeywell Agreement | Customer relationships
Intangible Assets, Net (Excluding Goodwill)
Intangible assets	900,000
June 2023 Honeywell Agreement | Licensing and certification rights
Intangible Assets, Net (Excluding Goodwill)
Intangible assets	100,000
September 2024 Honeywell Agreement | Backlog
Intangible Assets, Net (Excluding Goodwill)
Intangible assets	$ 6,300,000