The state of the art
The future trend in EV charging is toward "Share2" class charge ports (EVESE), such as the Tesla Wall Connector v2 and v3. This is designed for a whole stable of EVs to share one current capacity, and dynamically split the capacity amongst them. The ceiling on the shared ampacity is 100A under current designs. However this requires (really benefits from) a subpanel to distribute power to each EVSE.
You need a subpanel anyway, so might as well do it proper.
Here's the fatal flaw. At 60A circuit size, there are no affordable sockets. Therefore, the 48A continuous/60A breaker EVSE must be hardwired. Hardwired ones must have a disconnect switch in line-of-sight to the EVSE.
You can faff around with trying to buy a literal disconnect switch if you really want to, but the cheapest disconnect switch made is a subpanel.
A pitiful 2-space panel will suffice for a single EVSE, however, the cost differential for a larger subpanel is trivial (at least on total project cost). And the "regret cost" of needing more spaces later is much higher. Therefore, it is always "pennywise, pound foolish" to chintz out on subpanels. We advise "go big, really big". Even a 24 space panel has only about a $60 cost differential vs. a 2-space "disconnect enclosure".
The subpanel will also serve as the disconnect for a second EVSE should you go into the Share2 scheme.
For many types of EVSE, it is "power sharing" not "circuit sharing". E.G. the Tesla Wall Connector V2 can share up to 100A, but requires its own breaker/circuit per EVSE. And it is limited to 60A per EVSE (hence 60A breaker and 65A wire* may be used). So that means you need multiple 2-space breakers to serve as disconnects.
Wire or cable
If a suitable subpanel location is quite close to the main panel, the hands-down best way to plumb that is with non-flexible metal conduit such as EMT. That lets you throw in wires any size you want, assuming the conduit is big enough.
For very short runs I don't sweat the price of aluminum vs copper, it's more about availability. Certainly do not sweat aluminum's safety - that has never been questioned on feeders this large.
#2 aluminum is a commodity item (because it's used for 100A services to a dwelling due to a favorable derate, 310.15b7). For us mortals doing subpanel feeder, it's only good to 90A.
#4 copper is 85A for us. Breaker at 90A*.
For honest 100A you need #1Al or #3Cu.
How do we provision houses, anyway?
The number of breaker spaces in a house do not matter. The sum of all the breaker trips in a house do not matter.
Any house, when attached to the electrical grid, is the subject of a Load Calculation. This takes the square footage of the house (as a "catch-all" for general household lighting and small-appliance load, typically 3 VA (similar to watts) per square foot), certain receptacle circuits (kitchen and bathroom) at typically 1500 VA per circuit... a formula for certain large appliances, and straight nameplate data for other large appliances.
And common sense is applied: appliances are allowed to overlap if they won't be run simultaneously. (A/C and heat; wood shop and EVSEs; multiple tools in the wood shop when you have only one dust collector).
Even in subpanels, the operative language is "sufficient for the loads to be served".
Now the Load Calculation must be done at the time of the house's construction, as a condition of the permit. However it should be re-done when any large load is added, and EVSE's definitely qualify. If a permit was pulled to add the large load, this would be part of the permit process.
The beauty thing of an EVSE is that the ampacity is a "soft" (well, actually, "firm") setting. If you run a Load Calculation and find you only have 45A to spare for EV charging, then commission the EVSE to <=45A. This setting is done either in DIP switches or a very special and hard-to-access WiFi network. (this is a UL requirement to keep casual consumers from spiking their charge rates and setting their house on fire).
This is particularly helpful with multiple EVSEs and Share2 method. If you have three EVSE's and 50A to spare, rather than giving each EVSE 16 amps, you can give them all 50A to share, and they will "share on the fly". You can hasten one EV's charge by telling the other EV to defer charging for awhile.
* say what??? There is no wire with a 60A ampacity, it's all 55A or 65A. You are not allowed to plan to use more than actual wire ampacity, so a 48A/60A EVSE needs honest-60A wire, so 55A will not do and 65A wire must be used.
However if you have an odd size of wire like that, and you do not plan to use more than the honest ampacity (e.g. 85A) then you round up to the next available breaker (e.g. 90A). This is not license to plan to use those extra 5 amps!