8台
Valid switch numbers are 1 through 8 for Cisco Catalyst 9200 Series Switches. The port numbers of the member switches begin with the switch number, such as Gig1/0/1, Te1/1/1, or TwentyFiveGigE1/1/1, depending on whether the ports are Gigabit Ethernet (GE), 10 GE, or 25 GE.
Example: Switch 3 would have G3/0/1, Te3/1/1, TwentyFiveGigE3/1/1.
● Switch numbers are persistent, meaning that each switch keeps the same switch number after it reboots as a stack member, even if it is no longer part of the stack.
https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9200-series-switches/nb-06-stackwise-architecture-cte-en.html#_Toc13521183
