Is there a way to start and stop instances from the command line through awscli?

There sure is. Here’s stop

https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/stop-instances.html

Example

aws ec2 stop-instances \
    --instance-ids i-1234567890abcdef0

And here’s start

https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/start-instances.html

Example

aws ec2 start-instances \
    --instance-ids i-1234567890abcdef0