When you talked to "the dealer", who specifically did you talk to? A a salesperson? Sales Manager? F&I?
The latter is likely the best source, but unless they have leased a bunch of vehicles (and cared enough to look closely at the lease docs) that qualify for the Tax Credit, even they may not know.
The lease offer on Honda's website for the Clarity Plug-In for $389/mo with $2,999 due at signing does include a cap cost reduction of ~4K that is likely from the Tax Credit. Finance companies will also sometimes use the Tax Credit to "buy down" the Money Factor or in other ways that will result in a lower payment.
"Only for residents of the following ZEV States: CA, CT, ME, MD, MA, NJ, NY, OR, RI, VT
Closed-end lease for 2019 Clarity Plug-In Hybrid Continuously Variable Transmission available through 01/06/2020, to approved lessees by Honda Financial Services. MSRP $34,330.00 (includes destination; excludes tax, title, license, registration, options, insurance). Actual net capitalized cost $27,740.62. Total monthly payments $14,004.00. Option to purchase at lease end $14,761.90. Lessee responsible for maintenance, excessive wear/tear and up to 20¢/mi. over 12,000 miles/year. Dealer participation may affect actual payment. Dealer sets actual prices. See participating dealers for details."
Both the manufacturer and the dealer get the benefit of the Tax Credit as it is included in the selling price of the car, but
neither directly receive it. The finance company gets the credit, and while they are most often a division of the manufacturer (or wholly owned subsidiary), you are not obligated to finance/lease thru them (but often it is a condition of getting some of the factory incentives).